javascript 鼠标滚轮事件_javascript技巧

function wheelEvent(obj, handle)
{
this.handle = handle;
// different events between Firefox and IE
window.addEventListener ? obj.addEventListener("DOMMouseScroll", this.wheel, false) : (obj.onmousewheel = this.wheel);
}
wheelEvent.prototype.wheel = function (event)
{
var ev = event || window.event;
var delta = ev.wheelDelta ? (ev.wheelDelta / 120) : (- ev.detail / 3); // Firefox using `wheelDelta` IE using `detail`
eval ('delta ? ' + parent.handle + '(delta) : null;');
}

function handle(delta)
{
document.getElementById('text').scrollTop -= delta * 20;
}
new wheelEvent(document.getElementById('text'), 'handle');