Vanilla JS vs jQuery

vanilla.js

/*
	There is this file shared about the performance of vanilla JS and jQuery performance
	http://sharedfil.es/j-3k2NPAjwfQ.html	

	We are geeks and we want real numbers
	Test suite for www.jquery.com
	It is dummy test suite
	Chromium 18.0.997.0 (Developer Build 116462 Linux) Built on Ubuntu 11.10, running on LinuxMint 12
*/

window.prev_result = null;
var test = function (f) {
	var a,b;
	a = new Date().getTime();
	for(var i=0; i<1000; i++) {
		f();
	};
	b = new Date().getTime();
	
	var result = b-a;
	if(window.prev_result) {
		var diff = result / window.prev_result * 100;
		console.log(window.prev_result + " " + result + " " + diff);
		window.prev_result = null;
	} else {
		window.prev_result = result;
	}
};

// JQUERY milliseconds / RAW milliseconds / %

test(function() { var divs = $("div"); });
test(function() { var divs = document.querySelectorAll("div"); });
// 31 18 58.06451612903226

test(function() { var newDiv = $("<div />"); });
test(function() { var newDiv = document.createElement("div"); });
// 12 3 25

window.newDiv = $("<div />");
test(function() { window.newDiv.addClass("foo"); });
window.newDiv = document.createElement("div");
test(function() { window.newDiv.classList.add("foo"); });
// 18 3 16.666666666666664

test(function() { $("body").append("<p/>"); });
test(function() { document.body.appendChild(document.createElement("p")); });
// 27 5 18.51851851851852

test(function() { $("img").filter(":first").attr("alt", "Hi!"); });
test(function() { document.querySelector("img").setAttribute("alt", "Hi!"); });
// 78 7 8.974358974358974

test(function() { var parent = $("#jq-header").parent(); });
test(function() { var parent = document.getElementById("jq-header").parentNode; });
// 21 1 4.761904761904762

test(function() { var cloned = $("#jq-header").clone(); });
test(function() { var cloned = document.getElementById("jq-header").cloneNode(true); });
// 215 193 89.76744186046511

test(function() { $("#jq-header").empty(); });
test(function() { var wrap = document.getElementById("jq-header");
				  while(wrap.firstChild) wrap.removeChild(wrap.firstChild); });
// 7 1 14.285714285714285

test(function() { var nextElement = $("#jq-header").next(); });
test(function() { var nextElement = document.getElementById("jq-header").nextSibling; });
// 20 1 5