11.15对javascript this的理解，灾难源于这样的一段代码

javascript_this.js

/**
 *　关于事件监听最佳实践 　
 *  http://www.cnblogs.com/snowball/archive/2006/08/16/478531.html
 */ 


function associateObjWithEvent(obj, methodName){
    return (function(e){
        e = e||window.event;
       // obj  == DthmlObject , it's OK , but obj == new DthmlObject(),it's not

       //  what to do in new xxx(), #TODO 
          //for(i in obj.prototype) {
   　　  //console.log(i);
　　　　 //}
        return obj[methodName](e, this);　// error !!! 
       // return obj.prototype[methodName](e,this);  // 当这个函数复制给事件属性时，this在运行的时候才决定，为element.
    });
}
function DhtmlObject(elementId){
    var el = document.getElementById(elementId);
    if(el){
        // 
        //el.onclick = associateObjWithEvent(DhtmlObject, "doOnClick");
        //el.onmouseover = associateObjWithEvent(DhtmlObject, "doMouseOver");
        //el.onmouseout = associateObjWithEvent(DhtmlObject, "doMouseOut");
         // should use new DthmlObject() ， this  === DthmlOjbect ,otherwise this === windows
        el.onclick = associateObjWithEvent(this, "doOnClick");
        el.onmouseover = associateObjWithEvent(this, "doMouseOver");
        el.onmouseout = associateObjWithEvent(this, "doMouseOut");
    }
}
DhtmlObject.prototype.doOnClick = function(event, element){
    alert(element);
    // doOnClick method body.
}
DhtmlObject.prototype.doMouseOver = function(event, element){
    // doMouseOver method body.
}
DhtmlObject.prototype.doMouseOut = function(event, element){
    // doMouseOut method body.
}
new DhtmlObject("filetitle");
//DhtmlObject("filetitle");



参考资料： 


http://yehudakatz.com/2011/08/11/understanding-javascript-function-invocation-and-this/  作者相当的N。另外也讲到了对bind，对ecma 5的理解。