function zebra(id)
{
 if(document.getElementsByTagName)
 {  
   var table = document.getElementById(id);  
   var rows = table.getElementsByTagName("tr");  
   for(i = 0; i < rows.length; i++)
	{          
 //manipulate rows
     if(i % 2 == 0) 
	{
       rows[i].className = "even";
     }
	else{
       rows[i].className = "odd";
     }      
   }
 }
}