style-test.js

(function () {
	var start = new Date().getTime();

	var div = $('#content')[0];

	for (var i = 0; i < 1000000; i++) {
		if (i % 2 === 1) {
			div.className = '';
		} else {
			div.className = 'display-none';
		}
	}

	var end = new Date().getTime();
	var time = end - start;
	console.log('Execution time: ' + time);
})();