function tableruler()
{
 if (document.getElementById && document.createTextNode)
  {
   var tables=document.getElementsByTagName('table');
   for (var i=0;i<tables.length;i++)
   {
    if(tables[i].className=='ruler')
    {
     var trs=tables[i].getElementsByTagName('tr');
     for(var j=0;j<trs.length;j++)
     {
       trs[j].onmouseover=function(){this.id='hover';return false}
       trs[j].onmouseout=function(){this.id='';return false}
    }
   }
  }
 }
}
window.onload=function(){tableruler();}