function addClassName(elm, className){
	var currentClass = elm.className;
	if(!new RegExp(("(^|\\s)" + className + "(\\s|$)"), "i").test(currentClass)){
		elm.className = currentClass + ((currentClass.length > 0)? " " : "") + className;
	}
	return elm.className;
}

function removeClassName(elm, className){
	var classToRemove = new RegExp(("(^|\\s)" + className + "(\\s|$)"), "i");
	elm.className = elm.className.replace(classToRemove, "").replace(/^\s+|\s+$/g, "");
	return elm.className;
}

function turnOnPopup(link) {
	var listItem = document.getElementById(link);
	addClassName(listItem, 'turnOnThisPopup');
}

function turnOffPopup(link) {
	var listItem = document.getElementById(link);
	removeClassName(listItem, 'turnOnThisPopup');
}