function addClass(obj, myClass){
	obj.className = (obj.className == '') ? myClass : obj.className += ' ' + myClass;
}

function removeClass(obj, myClass){
	var a = String(obj.className).split(' ');
	var i = a.length;
	while(i--) if(a[i] == myClass) a.splice(i, 1);
	obj.className = a.join(' ');
}

function switchClass(obj, oldClass, newClass){
	var a = String(obj.className).split(' ');
	var i = a.length;
	while(i--) if(a[i] == oldClass) a[i] = newClass;
	obj.className = a.join(' ');
}

function switchClassInside(obj, oldClass, newClass){
	if(!obj.firstChild) return;
	var i = obj.childNodes.length;
	var e;
	while(i--){
		e = obj.childNodes[i];
		if(e.nodeType != 3){
			switchClass(e, oldClass, newClass);
			if(e.hasChildNodes) switchClassInside(e, oldClass, newClass);
		}
	}
}

function removeClassInside(obj, myClass){
	if(!obj.firstChild) return;
	var i = obj.childNodes.length;
	var e;
	while(i--){
		e = obj.childNodes[i];
		if(e.nodeType != 3){
			removeClass(e, myClass);
			if(e.hasChildNodes) removeClassInside(e, myClass);
		}
	}
}


function hasClass(obj, myClass){
	var a = String(obj.className).split(' ');
	var i = a.length;
	while(i--) if(a[i] == myClass) return true;
	return false;
}