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Web3.js Intro · Web3.js · #1 Ethereum Blockchain Developer Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 25494 Dapp University
Web3.JS: Ethereum JavaScript API
 
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Web3.js is the official Ethereum Javascript API. You use it to interact with your Ethereum smart contracts. Watch this talk about the new developments in Web3.js EVENT: devcon three 2017 SPEAKER: Fabian Vogelsteller PERMISSIONS: The original video was published with the Creative Commons Attribution license (reuse allowed). CREDITS: Original video source: https://www.youtube.com/watch?v=92pdrRH_VGA Additional material for JavaScript learners: https://amzn.to/2JrUINQ Eloquent JavaScript, 3rd Edition: A Modern Introduction to Programming https://amzn.to/2HwAMYd Simplifying JavaScript: Writing Modern JavaScript with ES5, ES6, and Beyond https://amzn.to/2Cq5bmL JavaScript: JavaScript Programming.A Step-by-Step Guide for Absolute Beginners https://amzn.to/2uhIvAP How JavaScript Works https://amzn.to/2CwS2bU The Modern JavaScript Collection
Views: 10348 Coding Tech
web3.js library, the Ethereum JavaScript API
 
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This video explains what the purpose is of the web3.js library and how to use it. The web3.js library is also known as the Ethereum JavaScript API. To communicate with an Ethereum node or transact with a smart contract deployed on the blockchain from inside a JavaScript or web application you can use the web3.js library. Under the hood the web3.js library communicates with an Ethereum node through JSON RPC calls. The Ethereum node must expose its a RPC layer. The MetaMask extension exposes the web3 API by an injected web3 object which you can access via JavaScript. The MetaMask extension does not support most synchronous web3 API methods. Make your method calls asynchronous! To use the web3.js library in your web application: - Download the web3.js library from: https://github.com/ethereum/web3.js - In the dist folder you will find the files web3-light.min.js and web3.min.js - The file web3.min.js contains the Bignumber module and the file web3-light.min.js does not. If you do not know which one to choose, then use file web3.min.js. Web3.js API code examples can be found at: http://www.mobilefish.com/download/ethereum/web3api.html In the examples asynchronous methods were used if they are available. The demonstration Ethereum Dapp is made for educational purpose. The web interface can be found at: http://www.mobilefish.com/download/ethereum/DemoDapp.html The associated Solidity contract can be found at: http://www.mobilefish.com/download/ethereum/DemoContract.sol.txt The main purpose of this Dapp is to learn how to use web3.js api (v0.x.x) and how interact with a deployed smart contract. To setup the demonstration Ethereum Dapp (DemoApp.html): - Download and deploy the DemoContract.sol smart contract on any test network (testrpc, ropsten, rinkeby, or your own private ethereum node, etc). Save the contract address you will need it later. - Download and install the DemoApp.html on your web server. - Download and install the web3.min.js (v0.19.0) on your web server. - Modify the path to web3.min.js in the DemoApp.html file. - Modify the contract address in the DemoApp.html file. How to use the demonstration Ethereum Dapp (DemoApp.html): - Use a test network. - Have a test account with enough ethers to experiment with. - The demonstration Dapp (DemoApp.html) also works well with MetaMask. Notes: Two versions of DemoApp.html has been created. - A version using callbacks which is not very readable because of using callback trees! For educational purpose you can find this version at (but do not use it!): http://www.mobilefish.com/download/ethereum/DemoDappv0.1.html - The original code has been refactored by using JavaScript Promises. http://www.mobilefish.com/download/ethereum/DemoDapp.html - The DemoApp.html uses only vanilla JavaScript an uses the web3.js library. All code meaning: JavaScript, HTML and CSS can be found in this single web page. Warnings: - The DemoApp.html does not work with the web3.js v1.0.0. - The web3.js library v1.0.0 has many changes. The DemoApp.html will soon be obsolete. - Use the Demonstration Ethereum Dapp on a test environment. Check out all my other Ethereum related tutorial videos: https://goo.gl/eNJVXe Subscribe to my YouTube channel: https://goo.gl/61NFzK The presentation used in this video tutorial can be found at: http://www.mobilefish.com/developer/blockchain/blockchain_quickguide_ethereum_related_tutorials.html The DemoContract.sol used in the video: http://www.mobilefish.com/download/ethereum/DemoContract.sol.txt To interact with the DemoContract.sol use the demonstration Ethereum Dapp (using Javascript Promises): http://www.mobilefish.com/download/ethereum/DemoDapp.html An older version of the demonstration Ethereum Dapp (do not use this): http://www.mobilefish.com/download/ethereum/DemoDappv0.1.html More information about RPC layer can be found at: https://youtu.be/oOfDzXBXoOg The web3.js library can be found at: https://github.com/ethereum/web3.js The web3.js API v0.x.x can be found at: https://github.com/ethereum/wiki/wiki/JavaScript-API The web3.js API v1.0 can be found at: http://web3js.readthedocs.io/en/1.0/ MetaMask web3 API can be found at: https://github.com/MetaMask/faq/blob/master/DEVELOPERS.md #mobilefish #howto #ethereum
Views: 16207 Mobilefish.com
03. Web3.js Tutorial - Attach a GUI to your Ethereum Smart Contract
 
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Free Course Page (In development): https://goo.gl/EiKpPP Written tutorial of this video: https://goo.gl/RdXuz9 https://coursetro.com This video is the 3rd lesson from my 100% free course: "Developing Ethereum Smart Contracts for Beginners" Check it out here: https://goo.gl/EiKpPP In this video, we're going to take our smart contract we created in the previous lesson, and make it accessible via a web page with the help of the official Ethereum Web3.js client and Ethereum-testrpc. https://coursetro.com https://www.facebook.com/coursetro/ - - - - - - - - - - - - - - - - - - - - - - Subscribe for NEW VIDEOS weekly! My site: https://coursetro.com My personal FB account: http://fb.com/logodesigner Coursetro FB: http://fb.com/coursetro Coursetro's Twitter: http://twitter.com/designcoursecom Join my Discord! https://discord.gg/a27CKAF ^-Chat with me and others - - - - - - - - - - - - - - - - - - - - - - Who is Gary Simon? Well, I'm a full stack developer with 2+ decades experience and I teach people how to design and code. I've created around 100+ courses for big brands like LinkedIn, Lynda.com, Pluralsight and Envato Network. Now, I focus all of my time and energy on this channel and my website Coursetro.com. Come to my discord server or add me on social media and say Hi!
Views: 74608 DesignCourse
Inside Ethereum Transactions · Web3.js · #3 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 7440 Dapp University
Deploying Smart Contracts · Web3.js · #4 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 5043 Dapp University
⛓️ Blockchain Developer Essentials PART 3: ETHEREUM Test RPC and Web3.js
 
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⛓️ Blockchain Developer Essentials PART 3: Test RPC and Web3.js | Vlad Wulf Blockchain Developer 😀😀😀 This is the part you've been waiting for. Learn how to bind you blockchain with your backend using http protocol and send data from the blockchain to the frontend. We are using Test RPC and Web3 version 1.0 👫 Social Networks: Mail: [email protected] LinkedIn: https://www.linkedin.com/in/vladimir-a-16334213b/ Steemit: https://steemit.com/@vladwulf Facebook: https://www.facebook.com/VladWulfTutorials/ Twitter: https://twitter.com/VladWulf 😍 Donations: Paypal: [email protected] Ether: 0x854F6C6C00Fc6e197B4f5aC48D1bac4210fE
Views: 8501 Vlad Wulf
Building a Ethereum Wallet API from Scratch!
 
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In this video I will be building from scratch a Basic Application that will Generate a Ethereum Wallet Address using Infura API, Display the Data, and then Parse the data via JSON over to the MongoDB. The tools I am using in this video are: MacOS High Sierra, Atom (as my text editor), npm (node package manager), Robo T3 (as the UI for the MongoDB). Here is the link to my github page where the finished project code is posted: https://github.com/webdev901/eth-wallet-address Here is the link I referenced in the video at the 12:00 minute mark: https://youtu.be/9jactlRcFwM Find more blockchain development resources at: https://web3devs.com/training/ Please leave a like and subscribe as it really helps support us.
Views: 442 web3devs
Ethereum SignatureStorage Dapp proof of concept using web3.js
 
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This video demonstrates the Ethereum SignatureStorage Dapp. This Dapp is a proof of concept how to store signatures in a smart contract. Disclaimer ------------------ The SignatureStorage Dapp is a proof of concept and should only be used for demonstration purpose. The SignatureStorage Dapp is not production ready. I have no legal experience. If you want to use this proof of concept (poc) you should contact a legal adviser in your country and verify if this poc is a legally sound solution. The SignatureStorage Dapp --------------------------------------------- The Ethereum SignatureStorage Dapp uses the web3.js v0.19.0 library. This proof of concept was created based on a discussion I had with a Dutch company which has a problem regarding to contracts and the signatures needed in order to close the deal. Problem description --------------------------------- Lets assume the ACME company wants to create a movie and hires two actors: Wily Coyote and Elmer Fudd. The ACME company (from now on referred to as “owner”) creates a paper contract and Wily and Elmer(from now on referred to as “signees”) both need to sign the contract in order to close the deal. For each signee, the owner creates a copy of the contract and the owner signs all 3 copies. The owner sends these 3 copies to Wily using the postal service. Wily signs these 3 copies and sends them back to the owner. The owner now sends the 3 copies to Elmer. Elmer signs these 3 copies, he keeps one copy and returns the other 2 to the owner. Finally the owner sends a copy to Wiley. The owner and signees now each have a copy of the contract with all the signatures. In case of a legal dispute each party can use their contract as evidence. Using paper contracts and actual signatures has pros and cons: Pros: - Easy to setup and use. Cons: - Using the postal service takes time compared with sending an email. - Using the postal service costs money think of: mail shipping rates and insurance. - The signees must send contracts back (extra burden for them). Of course the owner can use other solutions such as using SMS as signature or using signature images. But the owner always pays for these third party services. SignatureStorage Dapp ------------------------------------- The SignatureStorage Dapp is an alternative solution to paper contracts. The SignatureStorage Dapp uses the Ethereum blockchain. In this video I will demonstrate how to use the SignatureStorage Dapp and what the costs are. The SignatureStorage Dapp consists of two parts: - A web interface: https://www.mobilefish.com/download/ethereum/SignatureStorage.html - A solidity smart contract: https://www.mobilefish.com/download/ethereum/SignatureStorage.sol.txt Install SignatureStorage Dapp ------------------------------------------------ To install the SignatureStorage Dapp: - First deploy the smart contract. How to deploy a smart contract watch my video “Compile and deploy solidity code”: https://youtu.be/nnVX6fQUu4o - Next change the contract address in the SignatureStorage.html file. For more information watch my video“Ethereum contract Application Binary Interface”: https://youtu.be/F_l4HycnHAI - Download and install the two javascript libraries used by the SignatureStorage.html: The web3.min.js v0.19.0 https://github.com/ethereum/web3.js/tree/0.19.0/dist The sha256.js v3.1.2 https://code.google.com/archive/p/crypto-js/downloadsCryptoJS v3.1.2.zip Use the file: CryptoJS v3.1.2/rollups/sha256.js More information: https://code.google.com/archive/p/crypto-js - Install the SignatureStorage.html on a web server. How to use the SignatureStorage Dapp --------------------------------------------------------------- The SignatureStorage.sol is already deployed on the Rinkeby network. The contract address is: 0x2abdbeab89620b1d0837a9089a1b20447457fad2 Install the Chrome browser and install the MetaMask extension. For more information, watch my video: "MetaMask: How to restore your accounts”: https://youtu.be/cqz8-hOz_nk Open the SignatureStorage.html and click the help link. It will explain how to use the Dapp. Overview maximum transaction fees ----------------------------------------------------------- The Signature Storage Dapp is a proof of concept. I have made no effort to optimise the code to limit the number of operations and thus limit the gas usage. For users it is difficult to calculate the actual transaction fees. More information about transation fees watch my video “Ethereum gas, gas limit, gas price”: https://youtu.be/yFb2nuUUDX0 Check out all my other Ethereum related tutorial videos: https://goo.gl/eNJVXe Subscribe to my YouTube channel: https://goo.gl/61NFzK The presentation used in this video tutorial can be found at: https://www.mobilefish.com/developer/blockchain/blockchain_quickguide_ethereum_related_tutorials.html #mobilefish #howto #ethereum
Views: 1230 Mobilefish.com
Exploring Ethereum with Web3 Tutorial: Part 1 - Checking Balances
 
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Get FREE access to more content like this at http://www.techmaker.tv. Get a quick and easy understanding of how you can interact with Ethereum via Javascript. Helpful Links: Ethereum - http://ethereum.org/ Web3 - http://web3js.readthedocs.io/en/1.0/ Infura - http://infura.io/ Etherscan - http://www.etherscan.io
Views: 1870 TechmakerTV
Use Ethereum Blockchain With Python - Web3.py #6
 
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► SUBSCRIBE TO THIS CHANNEL ◄ Subscribe to become a highly paid blockchain developer: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 JOIN MY BLOCKCHAIN DEVELOPER BOOTCAMP: http://www.dappuniversity.com/bootcamp DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download Build Your first blockchain app: http://www.dappuniversity.com/articles/blockchain-app-tutorial Website: http://dappuniversity.com/ Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 944 Dapp University
Exploring Ethereum with Web3 Tutorial: Part 3 - Reading Smart Contract Events
 
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Get FREE access to more content like this at http://www.techmaker.tv. Get a quick and easy understanding of how you can interact with Ethereum via Javascript. In this episode, we look at what it means to create an ERC20 compliant smart contract on the Ethereum network, and we look at how to read the event stream with Web3.js. Helpful Links: Ethereum - http://ethereum.org/ Web3 - http://web3js.readthedocs.io/en/1.0/ Infura - http://infura.io/ Etherscan - http://www.etherscan.io
Views: 450 TechmakerTV
[이더리움 dAPP 만들기] web3.js 라이브러리 맛보기
 
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Management API : https://github.com/ethereum/go-ethereum/wiki/Management-APIs JSON RPC API : https://github.com/ethereum/wiki/wiki/JSON-RPC#go html 파일에 adding web3.js : https://github.com/ethereum/wiki/wiki/JavaScript-API#adding-web3 이더리움 dAPP 만들기 튜토리얼 기초 과정입니다. 이 강의에서 다룰 주제로는 Geth, Web3.js, Solidity, Truffle.js, Mist 등이 있고 추후에 더 추가될계획입니다.
Views: 1067 Solidify
Web3.js Utilities · Web3.js · #8 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1898 Dapp University
Ethereum dApp tutorial - Front end. Part 1
 
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Please read! In this video I introduce the tools that are needed to build a user interface that will allow interaction with the Ethereum blockchain. Web3.js github: https://github.com/ethereum/wiki/blob/master/JavaScript-API.md Meteor: https://www.meteor.com/ Meteor web3: https://atmospherejs.com/ethereum/web3 Metamask: https://metamask.io/ Meteor for begginers. Great tutorials: https://www.youtube.com/playlist?list=PLLnpHn493BHECNl9I8gwos-hEfFrer7TV Creating smart contracts using Solidity: https://www.youtube.com/playlist?list=PLH4m2oS2ratdoHFEkGvwvd7TkeTv4sa7Z If you loved this video, show me the love! BTC - 1LxhkGzGu6q2LSfAGuH2DNBChmLhHkuQzP ETH - 0x9f24bde4cD92560D04A159C30f46E7820e31d95c http://zeltsinger.com/
Views: 52659 Shlomi Zeltsinger
Using web3.js to interact with a deployed Ethereum smart contract
 
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Brian walks you through writing your first lines of web3 JavaScript code in order to interact with the Ethereum smart contract we deployed to the blockchain in the previous video. web3 JS documentation: https://github.com/ethereum/web3.js/ For professional inquiries, contact http://web3devs.com/
Frontend Web Applications On Ethereum 1 - TestRPC and Web3.js | Blockchain
 
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Ethereum allows you to create powerful smart contracts on the blockchain. The true power of Ethereum though, is the ability to create complex, decentralized applications or DApps. A great DApp ties smart contracts with an intunitive user-interface that allows the average user to leverage the power of the Ethereum network. In this video we begin to explore how to implement a web frontend that talks to our smart contracts deployed on the blockchain. Remix - Solidity IDE - https://remix.ethereum.org Solidity Documentation - https://solidity.readthedocs.io/en/develop/ ERC20 Standard - https://github.com/ethereum/eips/issues/20 EthereumJS TestRPC - https://github.com/ethereumjs/testrpc Web3JS - http://web3js.readthedocs.io/en/1.0/ Check out my other videos and articles http://edzynda.com Follow me on Steemit https://steemit.com/@edzynda 💎►Donate Ether and Ethereum-Based (ERC-20) Tokens 0x146cfed833cc926b16b0da9257e8a281c2add9f3 💎►Donate Bitcoin 1KyZbSeeCWgmeRrUQTTbb3meJEyPCGy3zd 💎►Donate Dash XoZdSzN3hPFksQQZx616A6fGGN22zANpMW 💎►Donate Lisk 16883042352161362207L 💎►Donate IOTA SRZWULMJI9WJFVWDIVXXMVWHVVJAKMAXKMFOINQGEZXNJYLRSHPXBE9PHQDUVIRESEUZSYJBGGKLBMEYIJOKIOIXBU
Views: 23663 What The Func?
Ethereum Dapp with React JS, Webpack, Web3 & Truffle
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download The Ultimate Ethereum Dapp Tutorial http://www.dappuniversity.com/articles/the-ultimate-ethereum-dapp-tutorial Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 13619 Dapp University
Solidity web3 watching events
 
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A short video on how to use web3.js to watch events which are triggered by a Solidity contract event function. We will continue with the professor html file and index.js file we have previously used in prior lectures. We will be adding an event function and watcher and writing it out to console.
Views: 835 Alex Luy
Smart Contract Events · Web3.js · #6 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) http://www.dappuniversity.com/articles/the-ultimate-ethereum-dapp-tutorial Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 3589 Dapp University
Solidity Event Listener in Web3
 
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In todays video we will look at how we can listen for events using the Web3 API. We will build a simple webpage that fetches data from a smart contract and will update it when events fire in the contract. The code is available here: https://github.com/filipmartinsson/Solidity/tree/master/bankevent
Views: 1141 Filip Martinsson
Deploy and Show Data Using Solidity and Web3 JS in ETH Blockchain #Part-04
 
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Deploy and Show Data Using Solidity and Web3 JS in ETH Blockchain #Part-04 GitHub Link: https://github.com/shojol80/BlockChainHelloWorld #banglatutorial #eth #blockchainbanglatutorial #ethreumbangla #cryptocurrency #soliditybanglatutorial #web3js #part4 Architecture #metamask #ethereum #cryptocurrency #blockchain #ico #noscam #welcome #thechange #love #ind #gandhiji #isupportcrypto #swachhcrypto #swachhbharat #crypto #cryptotrading #blockchainnews #investment #trustwallet #cryptonews #altcoin #blockchaintechnology #cryptolife #cryptotrader #bitcoin #mana #moneymaker #future #tecnologia #bhfyp #neo #lujo #lambo #bitcoincash #electroneumminingapp #criptomonedas #cointelegraph #bitcoinmining #litecoin #blockhain #coinmarketcap #art #coinbase #style #invest #binance #livecoin #eth #cryptocurrencies #hodl #tridentgold #etherium #etheriumgold #cryptoinvestor #cryptoinvesting #cryptoworld #goldinvestment #investing #investor #cryptopolitices #gandhiji #isupportcrypto #swachhcrypto #swachhbharat #crypto #cryptotrading #blockchainnews #investment #trustwallet #cryptonews #altcoin #blockchaintechnology #cryptolife #cryptotrader #bitcoin #mana #moneymaker #future #tecnologia #solarcoin What is Web3.js? Remember, the Ethereum network is made up of nodes, which each contain a copy of the blockchain. When you want to call a function on a smart contract, you need to query one of these nodes and tell it: The address of the smart contract The function you want to call, and The variables you want to pass to that function. Web3 Provider Remember, Ethereum is made up of nodes that all share a copy of the same data. Setting a Web3 Provider in Web3.js tells our code which node we should be talking to handle our reads and writes. It’s kind of like setting the URL of the remote web server for your API calls in a traditional web app. You could host your own Ethereum node as a provider. However, there’s a third-party service that makes your life easier so you don’t need to maintain your own Ethereum node in order to provide a DApp for your users — Infura. Infura Infura is a service that maintains a set of Ethereum nodes with a caching layer for fast reads, which you can access for free through their API. Using Infura as a provider, you can reliably send and receive messages to/from the Ethereum blockchain without needing to set up and maintain your own node. However, since our DApp is going to be used by many users — and these users are going to WRITE to the blockchain and not just read from it — we’ll need a way for these users to sign transactions with their private key. Note: Ethereum (and blockchains in general) use a public / private key pair to digitally sign transactions. Think of it like an extremely secure password for a digital signature. That way if I change some data on the blockchain, I can prove via my public key that I was the one who signed it — but since no one knows my private key, no one can forge a transaction for me. Cryptography is complicated, so unless you’re a security expert and you really know what you’re doing, it’s probably not a good idea to try to manage users’ private keys yourself in our app’s front-end. But luckily you don’t need to — there are already services that handle this for you. The most popular of these is Metamask. Metamask Metamask is a browser extension for Chrome and Firefox that lets users securely manage their Ethereum accounts and private keys, and use these accounts to interact with websites that are using Web3.js. (If you haven’t used it before, you’ll definitely want to go and install it — then your browser is Web3 enabled, and you can now interact with any website that communicates with the Ethereum blockchain!). And as a developer, if you want users to interact with your DApp through a website in their web browser (like we’re doing with our CryptoZombies game), you’ll definitely want to make it Metamask-compatible. Note: Metamask uses Infura’s servers under the hood as a web3 provider, just like we did above — but it also gives the user the option to choose their own web3 provider. So by using Metamask’s web3 provider, you’re giving the user a choice, and it’s one less thing you have to worry about in your app. Using Metamask’s web3 provider Metamask injects their web3 provider into the browser in the global JavaScript object web3. So your app can check to see if web3 exists, and if it does use web3.currentProvider as its provider. Here’s some template code provided by Metamask for how we can detect to see if the user has Metamask installed, and if not tell them they’ll need to install it to use our app. 2. Talking to Contracts Now that we’ve initialized Web3.js with MetaMask’s Web3 provider, let’s set it up to talk to our smart contract. Web3.js will need 2 things to talk to your contract: its address and its ABI.
Views: 150 Knowledge Seeker
Blockchain Exploitation 0x06 - Connecting to a Smart Contract with Web3.Js
 
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Connecting and hacking Ethereum contracts with web3.js 👊Please don't forget to smash those LIKE & SUBSCRIBE buttons :D 💎Donate Ether or any Ethereum-Based (ERC-20) Tokens: 0xdef4c066177CA2dA76FBDa7E249960D2a43D60D6 Github: https://github.com/cclabsInc/BlockCha... Contact Info: Console Cowboys Blog: http://console-cowboys.blogspot.com/ @Ficti0n on twitter: https://twitter.com/ficti0n http://cclabs.io http://consolecowboys.com
Views: 184 ConsoleCowboys
Send Ethereum Cryptocurrency With Python - Web3.py #2
 
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► SUBSCRIBE TO THIS CHANNEL ◄ Subscribe to become a highly paid blockchain developer: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 JOIN MY BLOCKCHAIN DEVELOPER BOOTCAMP: http://www.dappuniversity.com/bootcamp DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download Build Your first blockchain app: http://www.dappuniversity.com/articles/blockchain-app-tutorial Website: http://dappuniversity.com/ Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1322 Dapp University
Learn Smart Contracts · Web3.js · #2 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 9246 Dapp University
Tutorial dapp with Solidity, Truffle, Web3 and Javascript
 
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In this video, I tried to explain how to make simple dapp, app based on blockchain and Ethereum platform. App is consistent from Backend part smart contract written in Solidity using framework Truffle. Solidity is Ethereum language for writing smart contracts and Truffle is the most popular development framework for Ethereum with a mission to make your life a whole lot easier. During development we use testrpc. Testrpc is a Node.js based Ethereum client for testing and development. It uses ethereumjs to simulate full client behavior and make developing Ethereum applications much faster. It also includes all popular RPC functions and features (like events) and can be run deterministically to make development a breeze. In these way, we work on the local test network, not on the real network where we would spend real Gas. We use web3 to make your app work on Ethereum. Web3 object provided by the web3.js library. Under the hood, it communicates to a local node through RPC calls. web3.js works with any Ethereum node, which exposes an RPC layer. In frontend we connect with web3 we interact with backend blockchain and performing certain transactions. Then in standard way, we represent it in frontend with JS. For serving app we use Lite-Server Lightweight development only node server that serves a web app, opens it in the browser, refreshes when html or javascript change, injects CSS changes using sockets, and has a fallback page when a route is not found. Written version of this tutorial is here http://truffleframework.com/tutorials/pet-shop If you like the tutorial please leave the comment, subscribe and if you want, be free to donate some crypto: BTC: 12mqJi98dbS6xov4RrcYk2xhLnmZAyksYt ETH: 0x1cDB80B7a34F9fAC75AEC6ea4B68c985cBEA3c14 BCC: 8Fk2gHog9YMFUZUJcrGxFU2TtMPmwBtyW5 Write what you would like to see next, which blockchain development tutorial.
Views: 26905 Blockchain Talks
Ethereum for Python Developers
 
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Everything you need to know to get started with Ethereum with Python. Piper Merriam Ethereum Foundation python team lead.
Views: 4826 Ethereum Foundation
How to add Ethereum payments to your site with MetaMask
 
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Dead simple way to support Ether payments on your site. I'll show you how I added a support button to my site's page https://cryptojobslist.com/donate and now my visitors can support our project in just a few clicks Here is a simple code gist for your reference: https://cryptojobslist.com/blog/how-to-add-ethereum-payments-to-your-site-with-metamask
Views: 2143 Ksaitor
Geth communication
 
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Geth is the Go implementation of the Ethereum protocol. This tutorial demonstrates 4 ways to communicate with Geth: - Console mode using the JavaScript Runtime Environment - Script mode using the JavaScript Runtime Environment - Using HTTP (HypertextTransfer Protocol) The geth flags rpcapi, rpccorsdomain and rpc are explained. - Using IPC (Inter Process Communication) using the geth.ipc file. The geth flag ipcdisable is explained. This tutorial also explains what JSON-RPC is. Check out all my other Ethereum related tutorial videos https://goo.gl/eNJVXe Subscribe to my YouTube channel: https://goo.gl/61NFzK The presentation used in this video tutorial can be found at: https://goo.gl/snd1F4 JavaScript Runtime Environment https://github.com/ethereum/go-ethereum/wiki/JavaScript-Console JSON RPC API https://github.com/ethereum/wiki/wiki/JSON-RPC Management APIs https://github.com/ethereum/go-ethereum/wiki/Management-APIs Web3.js API https://github.com/ethereum/wiki/wiki/JavaScript-API Mobilefish.com: Using web3 API with MetaMask http://www.mobilefish.com/download/ethereum/web3api.html #mobilefish #howto #ethereum #geth
Views: 4876 Mobilefish.com
How To Sign Messages on Ethereum with Web3.js - Pt 1
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 CODE: https://github.com/dappuniversity/ecrecover DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1418 Dapp University
How to connect from JavaScript to Solidity using Web3.js and Truffle-Contract
 
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In this Ethereum Session I'll show you how to use Web3.js and Truffle-Contract on a lower-level. So you understand exactly how the communication between JavaScript and the Blockchain-Node works. This can be applied to any JavaScript Framework or even outside of that to any programming language. My Website: https://vomtom.at Ethereum Course: https://www.udemy.com/blockchain-developer/?couponCode=YOUTUBE15 GERMAN Ethereum Course 2018/19: https://www.udemy.com/ethereum-blockchain-entwicklung/?couponCode=YOUTUBE50 Code for the Ethereum Session: https://gist.github.com/tomw1808/f5146545e91895ac67bfea54717b352d Don't forget to subscribe to get updates! Let me know in the comments what you think.
Views: 1397 Thinking Assets
Calling A Smart Contract Method From Web3 (1.0) | Ep 4
 
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Let's learn how to call a smart contract method, once it is already deployed to the Ethereum network. Like this channel? Subscribe here: https://www.youtube.com/channel/UCZM8XQjNOyG2ElPpEUtNasA In this video tutorial for Ethereum we are going to use: - web3 for the JSON RPC client - Ethereumjs-testrpc for the Ethereum client We will learn the difference between calling a smart contract method using the eth_call vs using the eth_sendTransaction JSON RPC method. We will also learn about the concept of gas and gasPrice in transactions. Links: - Source Code: https://github.com/jklepatch/eattheblocks/tree/master/episode4 - Official Website https://eattheblocks.com - Author Website: https://www.julienklepatch.com
Views: 2090 Eat The Blocks
Build Ethereum Dapps With Python - Web3.py #4
 
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► SUBSCRIBE TO THIS CHANNEL ◄ Subscribe to become a highly paid blockchain developer: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 JOIN MY BLOCKCHAIN DEVELOPER BOOTCAMP: http://www.dappuniversity.com/bootcamp DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download Build Your first blockchain app: http://www.dappuniversity.com/articles/blockchain-app-tutorial Website: http://dappuniversity.com/ Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1270 Dapp University
Ethereum Dapp Tutorial, Part 2 of 3: Web Front-End with Metamask Integration
 
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https://steemit.com/tutorial/@hardlydifficult/ethereum-dapp-tutorial-part-2-of-3-web-front-end-with-metamask-integration #ethereum #dapp #buidl =========================== I'm not a financial adviser. Do your own research. Full disclosure, I own a lot of coins. My holdings: https://goo.gl/Vjn9iK Do not simply buy what I buy (I've made a lot of bad choices) #crypto Ledger Nano S is the hardware wallet I use and recommend: https://ledgerwallet.com/r/c241 Recommended Exchanges - Coinbase: https://coinbase.com/join/59ebf3c17be14a00f92091b8 - Binance: https://www.binance.com/?ref=15811261 Twitch: https://www.twitch.tv/HardlyDifficult Twitter: http://twitter.com/HardlyDifficult Steemit: https://steemit.com/@hardlydifficult Tips \o/ BTC: 3FQdCDmZcXXE8psTfazXxHKsdaLsXgxfWs ETH (incl any ERC20): 0x7A23608a8eBe71868013BDA0d900351A83bb4Dc2 LTC: MGF4vG8QT68otdbKT1ZjpqmFmkir67Wnjk NEO (incl any NEP5): AKSB636yR6wi4ivM7kJX3i999u3JGVgp5A DASH: XcCCFMgbNmCHiNEj1EbNGvSQBcRM8VCNNM BAN: ban_1597i1ybctywb37n5oikw79jyrrj7ocndaqad4foay861yeb1afppy3zxebz NANO: xrb_377ketnssiicfmruy6y7urhmbt1dkqprjwoob1nr8y7nxeixo4kuqx6gdm84 For business inquiries: [email protected]
Views: 1073 Hardly Difficult
Ethereum для начинающих. Geth JSON-RPC API.
 
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На этом уроке продолжаем изучать Geth и научимся использовать JSON-RPC API. https://github.com/ethereum/wiki/wiki/JSON-RPC - документация JSON-RPC API Geth.
Views: 564 doIT
Inspecting Blocks · Web3.js · #7 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1700 Dapp University
Создание web-приложения для взаимодействия с блокчейном Ethereum на платформе Meteor
 
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Курсы по разработке на Ethereum: http://ethereumworks.com/?ch=yts&utm_source=yts&utm_medium=youtubesl&utm_campaign=youtubesl&utm_term=youtubesl. Telegram чат для разработчиков: https://t.me/smart_contracts_dev; Самые свежие новости и статьи по криптокодингу - https://t.me/cryptocoding_news Предыдущее видео (создание и запуск первого умного контракта в сети Ethereum) - https://www.youtube.com/edit?o=U&video_id=Afr_PakSW5g Проект Meteor - https://www.meteor.com/ API пакета Web3 JavaScript - https://github.com/ethereum/wiki/wiki/JavaScript-API Sublime Text - https://www.sublimetext.com/ BAT файл для запуска Geth - https://drive.google.com/open?id=0B3_WGJKO-9L7X3hUbTFqZWFHWEk Cвязаться со мной можно через Skype - v.poskonin (Mouse Po). Канал можно поддержать отправив донат на биткоин-кошелек: 17Zs1nhgBB92CeCxFbbB7WhT9MdypJAj1d, или кошелек Ethereum: 0x9740Cd40296744a0aE2aFD115933a791Da4c2AD8.
Writing Smart Contracts · Web3.js · #5 Ethereum Blockchain Development Crash Course
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download How to Build Ethereum Dapp (Decentralized Application Development Tutorial) https://youtu.be/3681ZYbDSSk Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Website: http://dappuniversity.com/ Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 3189 Dapp University
Ethereum Smart Contracts With Python - Web3.py #3
 
14:37
► SUBSCRIBE TO THIS CHANNEL ◄ Subscribe to become a highly paid blockchain developer: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 JOIN MY BLOCKCHAIN DEVELOPER BOOTCAMP: http://www.dappuniversity.com/bootcamp DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download Build Your first blockchain app: http://www.dappuniversity.com/articles/blockchain-app-tutorial Website: http://dappuniversity.com/ Donate Ether to the channel: 0x39C7BC5496f4eaaa1fF75d88E079C22f0519E7b9 Follow me on Twitter (@DappUniversity): https://twitter.com/DappUniversity Email me: [email protected]
Views: 1412 Dapp University
Ethereum Web3/Solidity Workshop
 
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Repo: https://github.com/cmditch/hodl-box Slides: https://goo.gl/4tr56k Demo: https://cmditch.github.io/hodlbox (Run testrpc in the background)
Views: 3299 ETHDenver
Web3.js 1.0
 
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Speaker: Fabian Vogelsteller
Views: 5197 Ethereum Foundation
Deploy A Smart Contract With Web3 (1.0) | Ep 3
 
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Today we are going to deploy an Ethereum smart contract to a local testnet: - Using web3 for the JSON RPC client - Using Ethereumjs-testrpc for the Ethereum client - Using an interactive nodejs console for easier understanding - Detailed, step-by-step explanations of the process - Using the simple HelloWorld smart contract created at Episode 2 (link to source code below). Source code: https://github.com/jklepatch/eattheblocks/tree/master/episode3 Like this channel? Subscribe here: https://www.youtube.com/channel/UCZM8XQjNOyG2ElPpEUtNasA Links: - Official Website https://eattheblocks.com - Author Website: https://www.julienklepatch.com
Views: 2078 Eat The Blocks
3 Most Common Ways to create new Ethereum accounts - MEW Web3 Parity
 
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General Inquires: https://t.me/lingqingmeng Video notes: https://gist.github.com/lingqingmeng/d54a1d69e40ba7bb02dfc696d6666e77 Description: expand below ------------------- This video is me go over the most common ways to create an Ethereum account. I explain the tradeoffs between each method and go super indepth into explaining how each way differs. All in all with these 3 methods you should be equipped in the majority of situations
Views: 457 Ling Qing Meng
What is Oraclize? - Integrating APIs into your Solidity Contracts
 
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Welcome to this updated video on Oraclize. In this video I explain what Oraclize is and how to use it in Solidity. Sign up for our Smart Contract Course: coding.ivanontech.com Follow me on instagram: @martinsson_filip
Views: 769 Filip Martinsson
Exploring Ethereum with Web3 Tutorial: Part 2 - Interacting with Smart Contracts
 
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Get FREE access to more content like this at http://www.techmaker.tv. Get a quick and easy understanding of how you can interact with Ethereum via Javascript. In this episode, we dive into what a JSON ABI is, how to instantiate a new contract in Web3.js with your JSON ABI, and how to run functions on the smart contract with Javascript. Helpful Links: Ethereum - http://ethereum.org/ Web3 - http://web3js.readthedocs.io/en/1.0/ Infura - http://infura.io/ Etherscan - http://www.etherscan.io
Views: 882 TechmakerTV
Ethereum Geth 1.8.23 problem web3
 
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Прошу Помогите Разобраться с этой Проблемой!!! Непонятная проблема с Geth. Geth запущен с параметрами: [Unit] Description=Go Ethereum After=syslog.target network.target [Service] User=root LimitNOFILE=32768 ExecStart=/root/go-ethereum/build/bin/geth --syncmode=full --rpc --rpcaddr 127.0.0.1 --rpcport 45868 --rpccorsdomain "*" --rpcapi admin,debug,miner,shh,txpool,personal,eth,net,web3 --cache=32768 [Install] WantedBy=multi-user.target Подключение делаю с помощью: var express = require('express'); const Web3 = require('web3'); var web3; web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:45868")); Основна проблема не проходят команди за допомогою web3 інтерфейса. Команди виконуються якось страно. Команда из консоли Geth: web3.fromWei(eth.getBalance("0x6996DA0383066aEb5a52F65B0b9eb1981B3c7867"), 'ether'); Команда API web3: web3.fromWei(web3.eth.getBalance("0x6996DA0383066aEb5a52F65B0b9eb1981B3c7867").toNumber(), 'ether');
Views: 63 Viktor Soft
1. Deploy Smart Contracts Remix + Ropsten Ethereum Network
 
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► SUBSCRIBE TO THIS CHANNEL ◄ For more videos on how to build decentralized applications on The Ethereum Blockchain: https://www.youtube.com/channel/UCY0xL8V6NzzFcwzHCgB8orQ?sub_confirmation=1 DOWNLOAD FREE VIDEO COURSES: http://www.dappuniversity.com/free-download The Ultimate Ethereum Dapp Tutorial http://www.dappuniversity.com/articles/the-ultimate-ethereum-dapp-tutorial
Views: 7813 Dapp University
Learning Solidity : Tutorial 32 Transferring ether with Java using web3j
 
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Homepage of solidity : https://solidity.readthedocs.io/en/develop/ Remix : http://remix.ethereum.org Source code : https://github.com/willitscale/learning-solidity If you would like to donate some Ethereum my wallet is: 0xC8c8c3Fae80e3eD236970e1C93AcF5B91D0993e2 Many thanks! Web3j Documentation : https://docs.web3j.io/ Web3j command line client : https://github.com/web3j/web3j/releases/tag/v3.6.0 Solidity compiler : https://github.com/ethereum/solidity/releases
Views: 1581 Will it Scale