function alternate(id){
	if(document.getElementsByTagName){
		var table = document.getElementById(id);
		var rows = table.getElementsByTagName("tr");
		for(i = 0; i < rows.length; i++){

			if(i % 2 == 0){
				rows[i].className = "even";
			}else{
				rows[i].className = "odd";
			}
		}
 	}
}