// Change Background trick
function hatTrick(hatNumber, subset) {
	var total = 10;
	var bodyTag = document.getElementsByTagName('body')[0];
	var classList = bodyTag.className;
	if (classList.indexOf("hat") > -1) {
		var tempClasses = new Array();
		var classes = classList.split(" ");
		var j = 0;
		for(i = 0; i < classes.length; i++) {
			if(classes[i].substr(0,3) != "hat") tempClasses[j++] = classes[i];
		}
		classList = tempClasses.join(" ");
	}

	if (!hatNumber) hatNumber = Math.floor(total*Math.random());
	var newHat = " hat" + hatNumber;
	bodyTag.className = classList + newHat + "";
}