if(document.getElementById){
    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 = rows[i].className + "even";
				}
				else{
				    rows[i].className = rows[i].className + "odd";
				}
			}         
		}
	}
}