Async javascript loading (with saving order).

async-javascript-loading.js

/*
  The main feature is script.async = false. 
  The async IDL attribute controls whether the element will execute asynchronously or not.
  So if you will set async to false, scripts will load without blocking user i/o, but scripts will execute synchronously.
  Support: 
    FF 4+
    FF for Android All Versions
    IE 10+ (starting with preview 2)
    Chrome 12+
    Chrome For Android All versions
    Safari 5.1+
    iOS Safari 5.1+
    Android Browser 3.0+ (honeycomb on up)
    Opera 15.0+
    Opera Mobile 16.0+
*/

[
  '1.js',
  '2.js'
].forEach(function(src) {
  var script = document.createElement('script');
  script.src = src;
  script.async = false;
  document.head.appendChild(script);
});