fast_setTimeout.js

var orig_setTimeout = window.setTimeout;
window.setTimeout = function (fun, wait) {
	if (wait < 15) {
		orig_setTimeout(fun, wait);
	} else {
		var img = new Image();
		img.onload = img.onerror = function () {
			fun();
		};
		img.src = "data:,foo";
	}
};

setTimeout(function () {
	alert(navigator.userAgent);
	document.body.addEventListener("click", function () { alert('click') }, false);

	var prevTime = new Date().getTime();
	var results  = [];
	setTimeout(function () {
		var now = new Date().getTime();
		results.push(now - prevTime);
		if (results.length < 500) {
			prevTime = new Date().getTime();
			setTimeout(arguments.callee, 0);
		} else {
			document.body.appendChild(document.createTextNode(results.join(" ")));
			var avg, sum = 0;
			for (var i = 0; i < results.length; i++) {
				sum += results[i];
			}
			avg = sum / results.length;

			results.sort();
			var min = results[0];
			var max = results[results.length - 1];

			document.body.appendChild(document.createTextNode(" avg:" + avg + " min:" + min + " max:" + max));
		}
	}, 0);
}, 1000);