function checkItems() {
var u,l;
var table=document.getElementsByTagName("table");	  
   for (u=0; u<table.length; u++) {
	  tr=table[u].getElementsByTagName("tr");
 	  doEven(tr);
  }
}

function doEven(myRows) {
  for (l=0; l<tr.length; l++) {
    if (l%2==0) { tr[l].setAttribute('class', 'altrow'); tr[l].setAttribute('className', 'altrow'); } 
  }
}

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

addLoadEvent(checkItems);