function changebg(cl) {		
		var events = getElementsByClass(cl);
		for(var i = 0; i < events.length; i++) {
			events[i].style.background = 'orange';			
		}
	}

	
	function returnbg(cl) {				
		var events = getElementsByClass(cl);
		for(var i = 0; i < events.length; i++) {
			events[i].style.background = '#FFFFFF';			
		}
	}

	
	function getElementsByClass(searchClass,node,tag) {
		var classElements = new Array();
		if ( node == null )
			node = document;
		if ( tag == null )
			tag = '*';
		var els = node.getElementsByTagName(tag);
		var elsLen = els.length;
		var pattern = new RegExp('(^|\\s)'+searchClass+'(\\s|$)');
		for (i = 0, j = 0; i < elsLen; i++) {
			if ( pattern.test(els[i].className) ) {
				classElements[j] = els[i];
				j++;
			}
		}
		return classElements;
	}