添加/移除事件

eventListener.js

var addEvent,removeEvent;

addEvent = function(elm, evType, fn, useCapture) {
  if (elm.addEventListener) { 
    elm.addEventListener(evType, fn, useCapture);//DOM2.0 
    return true; 
  }else if (elm.attachEvent) { 
    var r = elm.attachEvent('on' + evType, fn);//IE5+ 
    return r; 
  }else { 
    elm['on' + evType] = fn;//DOM 0 
  } 
};

removeEvent = function(elm, evType, fn, useCaptrue){
  if (elm.removeEventListener) { 
    elm.removeEventListener(evType, fn, useCapture);//DOM2.0 
    return true; 
  }else if (elm.detachEvent) { 
    var r = elm.detachEvent('on' + evType, fn);//IE5+ 
    return r; 
  }else { 
    elm['on' + evType] = null;//DOM 0 
  }
}