function addClass(element, value){
	if(!element.className){
		element.className = value;
		} else {
			newClassName = element.className;
			newClassName+= " ";
			newClassName+= value;
			element.className = newClassName;
		}
}
function hightlightRows(){
	if(!document.getElementsByTagName) return false;
	var rows=document.getElementsByTagName("tr");
	for (var i=0;i<rows.length;i++) {
		rows[i].oldClassName=rows[i].className;
		rows[i].onmouseover=function() {
			addClass(this, "hightlight");
			}
			rows[i].onmouseout=function() {
				this.className=this.oldClassName
			}
		}
}
function hightlightHeads(){
	if(!document.getElementsByTagName) return false;
	var rows2=document.getElementsByTagName("th");
	for (var i=0;i<rows2.length;i++) {
		rows2[i].oldClassName=rows2[i].className;
		rows2[i].onmouseover=function() {
			addClass(this, "cabecera");
			}
			rows2[i].onmouseout=function() {
				this.className=this.oldClassName
			}
		}
}

function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload !='function') {
		window.onload = func;
		} else {
			window.onload=function() {
				oldonload();
				func();
			}
		}
	}
addLoadEvent(hightlightRows);
addLoadEvent(hightlightHeads);