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);