remy

var iframedelay = (function () {
  var iframedelay = { active : false },
      iframe = document.createElement('iframe'),
      doc,
      callbackName = '__callback' + (+new Date);

  iframe.style.height = iframe.style.width = '1px';
  iframe.style.visibility = 'hidden';
  document.body.appendChild(iframe);
  doc = iframe.contentDocument || iframe.contentWindow.document;

jeromeetienne

/**
 * precise version of Date.now() -
 * It provide submillisecond precision based on window.performance.now() when 
 * available, fall back on Date.now()
 * see http://updates.html5rocks.com/2012/05/requestAnimationFrame-API-now-with-sub-millisecond-precision 
*/
var nowSubms	= (function(){
	var p	= window.performance	|| {};
	if( p.now )		return function(){ return p.timing.navigationStart + p.now();		};
	else if( p.mozNow )	return function(){ return p.timing.navigationStart + p.mozNow();	};