// onmouseover
function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}
var btns = document.getElementsByTagName('input');
function btnHover(){
for(i=0;i<btns.length;i++){
	if (btns[i].className=="btnW1"||btns[i].className=="btnW2"||btns[i].className=="btnW3")
	{	
		btns[i].onmouseover=function(){
			this.style.backgroundPosition='0 -25px';
			}
		btns[i].onmouseout=function(){
			this.style.backgroundPosition='0 0';
			}
		}
	}
}
if(!window.XMLHttpRequest)
{
	addLoadEvent(btnHover);
}