function alternate(){
	if(document.getElementsByTagName){  
		var tables = document.getElementsByTagName("table");
		for(x = 0; x < tables.length; x++){   
			var rows = tables[x].getElementsByTagName("tr");  
			for(i = 0; i < rows.length; i++){          
				if(i % 2 == 0){
					rows[i].className = "even";
				}else{
					rows[i].className = "odd";
				}
			}
		}
	}
}
window.onload = alternate;