45. var ajax = new XMLHttpRequest();
ajax.onreadystatechange = function(js){
if (ajax.readyState == 4)
// execute js in order
};
ajax.open('script.js');
ajax.send();
Ajax
46. var js = document.createElement('script');
js.src = 'script.js';
IE
47. var js = document.createElement('script');
js.src = 'script.js';
IE
js.onreadystatechange = function(){
if (js.readyState == 'loaded')
document.head.appendChild(js);
};