JS滚轮事件(mousewheel/DOMMouseScroll)

兼容滚轮事件的方法
兼容 safari，chrome和firefox的函数
var addEvent = (function(window, undefined) {
  var _event = function(event) {
    var type = event.type;
    if (type === 'DOMMouseScroll' || type === 'mousewheel') {
      console.log(event)
      event.delta = (event.wheelDelta) ? event.wheelDelta / 120 : -(event.detail || 0);
    }
    if (event.srcElement && !event.target) {
      event.target = event.srcElement;
    }
    if (!event.preventDefault && event.returnValue !== undefined) {
      event.preventDefault = function() {
        event.returnValue = false;
      }
    }
    return event;
  };
  if (window.addEventListener) {
    return function(el, type, fn, capture) {
      if (type === 'mousewheel' && document.mozFullScreen !== undefined) {
        type = "DOMMouseScroll";
      }
      el.addEventListener(type, function(event) {
        fn.call(this, _event(event));
      }, capture || false);
    }
  } else if (window.attachEvent) {
    return function(el, type, fn, capture) {
      el.attachEvent("on" + type, function(event) {
        event = event || window.event;
        fn.call(el, _event(event));
      });
    }
  }
})(window);

测试使用方法如下：

addEvent(window, "mousewheel", function(event) {
  console.log(event.delta);
  if(event.delta < 0) {
    console.log('鼠标向下滚动了');
  }
});