PhantomJS sample script

crawl.js

var page = require('webpage').create();

page.onConsoleMessage = function(msg) {
    console.log(msg);
};

page.open("http://www.somewebsite.com", function(status) {
    if ( status === "success" ) {
        page.evaluate(function() {
              document.querySelector("input[name='MAIL_ADDRESS']").value = "[email protected]";
              document.querySelector("input[name='PASSWORD']").value = "mypassword";
              document.getElementsByName("LOGIN_FORM_SUBMIT")[0].click();
              console.log("Login submitted!");
        });
        window.setTimeout(function () {
            page.render('screenshot.png');
            var ua = page.evaluate(function () {
                return document.getElementById('AnElementIdOnMyWebsite').innerText;
            });
            console.log(ua);
            phantom.exit();
        }, 5000);
   }
});