function addClass(target, classValue) {
	if (!hasClass(target, classValue))
		if (target.className == "")
			target.className = classValue;
		else
			target.className += " " + classValue;
	return true;
};

function removeClass(target, classValue) {
	var removedClass = target.className;
	var pattern = new RegExp("(^| )" + classValue + "( |$)");
	removedClass = removedClass.replace(pattern, "$1");
	removedClass = removedClass.replace(/ $/, "");
	target.className = removedClass;
	return true;
};

function hasClass(target, classValue) {
	var pattern = new RegExp("(^| )" + classValue + "( |$)");    
	if (target.className.match(pattern))
		return true;
	return false;
};

function isin(element, set) {
	for(var j = 0; j < set.length; j++) {
		if (element == set[j]) {
			return true;
		}
	}
	return false;
}


function removeChildNodes(element) {
	while (element.childNodes[0]) {
		element.removeChild(element.childNodes[0]);
	}
}