未捕获的ReferenceError：app.js中未定义require：3

Question

Having issue while connecting front-end HTML to private blockchain in order to interact with the smart contract.

Step completed as below:

• created a smart contract and deployed in pvt blockchain.
• npm install -g web3
• created HTML file and linked with below js file.

// Sample app.js file code

var Web3 = require('web3');
var web3 = new Web3();

if (typeof web3 !== 'undefined') {alert(" web3.currentProvider :: " + web3.currentProvider);
    web3 = new Web3(web3.currentProvider);
} else {
    // set the provider you want from Web3.providers
    web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
 }

 var abi= My-custom-ABI;


 var ins=web3.eth.contract(abi);
 var instance= ins.at("My-Contract-Address");
 var accounts;
 var account;
 var account2;

Answer 1

You should install it as your dependency, try npm install --save web3 . Also, you need webpack to transpile your javascript, because browser don't understand require syntax.