事件及兼容性处理

var event = (function () {
  var listener = function (ele, type, fn) {
    (listener =
      ele.addEventListener ?
        niceListener : IEListener
    )(ele, type, fn);
  };
  var remove = function (ele, type, fn) {
    (remove =
      ele.removeEventListener ?
        niceRemove : IERemove
    )(ele, type, fn);
  };
  return {
    listener: listener,
    remove: remove
  }
})();
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function IERemove(ele, type, fn) {
  var eventCbArr = ele["handleEvent" + type],
    i = 0,
    len = eventCbArr.length;
  if (eventCbArr && len) {
    for (; i < len; i++) {
      if (eventCbArr[i] == fn) {
        return eventCbArr.splice(i, 1);
      }
    }
  }
}
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function IEListener(ele, type, fn) {
  eventPush(getEventList(ele, type), fn);
  return ele;
}
function eventPush(eventCbArr, fn) {        
  for (var i = 0; i < eventCbArr.length; i++) {
    if (eventCbArr[i] == fn) {
      return;
    };
  }
  eventCbArr.push(fn);
}
function getEventList(ele, type) {
  if (!ele["handleEvent" + type]) {
    ele.attachEvent("on" + type, function () {
      runCb(ele, eventHandle(e));
    });
  }
  return ele["handleEvent" + type];
}
function runCb(elm, event) {
  var ary = elm["handleEvent" + event.type];
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  for (var i = 0; i <= ary.length;) {
    var cb = ary[i];
    if (typeof cb === "function") {
      cb.call(elm, e);               //  监听函数的this
      i++;
    } else {
      ary.splice(i, 1);
    }
  }
}
//不再額外考虑 IE 678 的兼容
function eventHandle(e) {
  e = window.event;
  e.target = e.srcElement;
  e.pageX = (document.documentElement.scrollLeft ||
    document.body.scrollLeft) + e.clientX;
  e.pageY = (document.documentElement.scrollTop ||
    document.body.scrollTop) + e.clientY;
  e.stopPropagation = function () { e.cancelBubble = true; }  // 阻止事件进一步传播
  e.preventDefault = function () { e.returnValue = false; }  // 阻止事件的默认行为：
  return e;
}
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function niceRemove(ele, type, fn) {
  ele.removeEventListener(type, fn);
  return ele;
}
function niceListener(ele, type, fn) {
  ele.addEventListener(type, fn, false);
  return ele;
}