Like this?
nu = nu + 1
Code:
function GoTo(id,nu){
var obj=document.getElementById(id),trs=obj.getElementsByTagName('TR');;
nu = nu + 1
if (trs[nu]){
if (GoTo.lst&&GoTo.lst!=trs[nu]){
GoTo.lst.className='';
}
trs[nu].className = trs[nu].className=="highlighted" ? "" : "highlighted";
GoTo.lst=trs[nu];
}
}