Using just 41 lines of HTML + JS, we create a Web3.JS application which can get the ETH Balance of an Ethereum Address
Read my Blog Post here: http://shawntabrizi.com/crypto/ethereum-web3-js-hello-world-get-eth-balance-ethereum-address/
Read my correction to my original sample here: http://shawntabrizi.com/crypto/correcting-ethereum-web3-js-hello-world/
Try it out here: http://shawntabrizi.com/ethbalance/
Using Web3.js: https://github.com/ethereum/web3.js
Using Infura.io: https://infura.io/