PhantomJS

PhantomJS : headless WebKit scriptable with a JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas, and SVG. http://phantomjs.org/

CasperJS http://casperjs.org/ : navigation scripting & testing utility for PhantomJS and SlimerJS written in Javascript

console.log('Loading a web page');
var page = require('webpage').create();
var url = 'http://www.phantomjs.org/';
page.open(url, function (status) {
  //Page is loaded!
  phantom.exit();
});

./bin/phantomjs loadpage.js