Ethereum Cookbook

How to do it...

Now, we will start with the steps that are needed to use MetaMask as an injected provider:

1. Initialize web3 using the provider object injected by the browser providers:

// For v0.2x.xvar web3 = new Web3(web3.currentProvider);// For v1.x.xvar web3 = new Web3(Web3.givenProvider);

2. Check for existing providers to ensure that you are not overwriting the existing Mist or MetaMask provider:

// For v0.2x.xif (typeof web3 !== 'undefined') {
  web3 = new Web3(web3.currentProvider);
} else {
  web3 = new Web3(     new Web3.providers.HttpProvider("http://localhost:8545")  );
}// For v1.x.xvar web3 = new Web3(Web3.givenProvider || "ws://localhost:8546");

MetaMask cannot communicate to applications running directly from a filesystem through ...