Array.prototype.indexOf = function(a) {
	for (var b = 0; b < this.length; b++) {
		if (this[b] === a) return b;
	}
	return false;
}
Array.prototype.contains = function(a) {
	for (var b = 0; b < this.length; b++) {
		if (this[b] === a) return true;
	}
	return false;
}
Array.prototype.remove = function(a) {
	this.splice(a, 1);
	return this.length;
}

function chgSortLocation(a) {
	var b = a.options[a.selectedIndex].value;
	if (b != '') window.location = b;
}

function chgCmpProducts(a) {
	if (a.checked) {
		if (cmpProducts.length >= 4) { 
			alert('Es können maximal 4 Produkte verglichen werden.'); 
			a.checked = false;
			return;
		}
		if (!cmpProducts.contains(a.value)) cmpProducts.push(a.value);
		return;
	}
	if (!cmpProducts.contains(a.value)) return;
	cmpProducts.remove(cmpProducts.indexOf(a.value));
}

function chgCmpLocation(a) {
	if (!cmpProducts.contains(a) && cmpProducts.length < 4) cmpProducts.push(a);
	window.location = "/produktvergleich/" + cmpProducts.join("-");
}