function alternate(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"; 
   		}
 	}
}