鼠标中键滚动事件

if (window.addEventListener){
window.addEventListener('DOMMouseScroll', wheel, false);
window.onmousewheel = document.onmousewheel = wheel;

}

function wheel(event){
scrollFunc(event);
var delta = 0;
if (!event) event = window.event;
if (event.wheelDelta) {
delta = event.wheelDelta/120;
if (window.opera) delta = -delta;
}
else if (event.detail)
{
delta = -event.detail/3;
}
if (delta)
  alert(delta);
}
//防止滚动条引起的抖动
var scrollFunc=function(e){
e=e||window.event;
if (e&&e.preventDefault)
{
e.preventDefault();
e.stopPropagation();
}
else
{
e.returnvalue=false;
return false;
}
}