function altRows(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 = "evenrowcolor";
			}else{
				rows[i].className = "oddrowcolor";
			}      
		}
	}
}
 
window.onload=function(){
	altRows('alternatecolor');
}