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";
			}
		}
	}
}