js对象的内部方法使用apply后，如何在方法内访问自身对象

比如我创建了一个自定义对象var myobj={
item:null,

self:null,

init:function(obj){
this.item=obj;
this.self=this;
this.addEvent.apply(this.item,['mousedown',this.bind]);
}, addEvent:function(type,listener){
if(this.addEventListener)
{
this.addEventListener(type,listener,false);
}
else
{
this.attachEvent('on'+type,listener);
}
}, bind:function(){

},
}在myobj初始化后执行addEvent绑定事件，然后问题就出现了，到bind函数里面，如果使用this，这个this是myobj.item，我要想访问自身，该怎么办？

解决方案 »

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在外面定义一个var othis = this;
里面就可以用othis了．
是的在全局顶一个 var othis = this; 但是貌似很浪费性能。。
记住addEvent是你的myobj的专有方法不是给别人（其他对象）用的
如果是给大家一起用的就要提取来成为一个公共APIinit:function(obj){
        //。
        //this.addEvent('mousedown',this.bind]); 这个不要了没意义
       var item=this.item;
       var me=this;
       if(item.addEventListener)
        {
            item.addEventListener('mousedown',function(){ me.bind(); },false);
        }
        else
        {
            item.attachEvent('onmousedown',function(){ me.bind(); } );
        }
        //对自己内部dom的绑定就直接写如果想套方法就把事件绑定提取成公共的
        //注意上面me的用法
    },
var myobj = {
    item: null,

    self: null,

    init: function(obj) {
        this.item = obj;
        this.self = this;
        this.addEvent.apply(this.item, ['mousedown',this.wrapper(this, this.bind)]);
    },
wrapper: function(target, fn) {
return function() {
fn.apply(target);
}
},
    addEvent: function(type, listener) {
        if (this.addEventListener) {
            this.addEventListener(type, listener, false);
        } else {
            this.attachEvent('on'+type,listener);
        }
    },    bind: function(){

    }
}
addEvent  不是为了注册事件嘛。。
为什么不把这句this.addEvent.apply(this.item,['mousedown',this.bind]);
直接换成 this.item.onmousedown = this.bind;    addEvent 方法应该可以去掉..还分浏览器那要考虑..不明白为什么  求解！！~
  this.addEvent.apply(this.item,['mousedown',function(){var o = this;return function(){o.bind()}}.call(this)]);
还有一种方法，是ECMAScript5推荐的写法
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
function addEventListener(target, eventName, fn) {

if (target.addEventListener) {
target.addEventListener(eventName, fn, false);
} else {
target.attachEvent('on' + eventName, fn);
}
}

window.onload = function() {
var testObj = {
name: "123",
init: function() {
var test = document.getElementById("test");
addEventListener(test, "click", this.dispatch.bind(this));
},
dispatch: function() {
alert(this.name);
}
};
testObj.init();
}

</script>
</head>
<body>
<div id="test" style="width:400px; height:300px; border-style:solid; border-width:1px; background-color:#ffffff"></div>
</body>
</html> Browser Support
○　Firefox 4
○　Internet Explorer 9
○　Chrome 7+
用你的方法又发现一个问题，就是想要解除绑定解除不了
比如我这样：<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
var myobj = {
    item: null,

    self: null,

pro:1,

    init: function(obj) {
        this.item = obj;
        this.self = this;
        this.addEvent.apply(this.item, ['mousedown',this.wrapper(this, this.bind)]);
this.addEvent.apply(this.item, ['mouseup',this.wrapper(this, this.unbind)]);
    },

    wrapper: function(target, fn) {
        return function() {
            fn.apply(target);
        }
    },
    addEvent: function(type, listener) {
        if (this.addEventListener) {
            this.addEventListener(type, listener, false);
        } else {
            this.attachEvent('on'+type,listener);
        }
    },

removeEvent:function(type,listener)
{
if(this.removeEventListener)
{
this.removeEventListener(type,listener,false);
}
else
{
this.detachEvent('on'+type,listener);
}
},

    bind: function(){
        this.addEvent.apply(this.item, ['mousemove',this.wrapper(this, this.getEventPoint)]);
    },

unbind: function(){
        this.removeEvent.apply(this.item, ['mousemove',this.wrapper(this, this.getEventPoint)]);
    },

getEventPoint:function(event){
var evt=event||window.event;
document.getElementById('test').innerHTML=evt.clientX+":"+evt.clientY;
}
}
window.onload=function(){
var obj=document.getElementById('test');
myobj.init(obj);
}</script>
</head>
<body>
    <div id="test" style="width:400px; height:300px; border-style:solid; border-width:1px; background-color:#ffffff"></div>
</body>
</html>本意是想在框内按下鼠标时能监测鼠标位置，不按的时候解除绑定，不再监测，可是实际情况是会一直绑定着，不知道该如何解除。
PS:因为在getEventPoint方法里还想用到对象本身，所以需要使用wrapper方法包装this。如果不用包装的话，能正常解除绑定的。
另外，wrapper这个方法在chrome和IE8下使用没出问题，但firefox5似乎在 fn.apply(target);这一句停下来
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
var myobj = {
    item: null,

    self: null,

    pro:1,

    init: function(obj) {
        this.item = obj;
        this.self = this;
        this.handler = this.wrapper(this, this.getEventPoint);
        this.addEvent.apply(this.item, ['mousedown', this.wrapper(this, this.bindMouse)]);
        this.addEvent.apply(this.item, ['mouseup', this.wrapper(this, this.unbindMouse)]);
    },
    bindMouse: function() {
     this.addEvent.apply(this.item, ["mousemove", this.handler]);
    },
    unbindMouse: function() {
     this.removeEvent.apply(this.item, ["mousemove", this.handler]);
    },
    wrapper: function(target, fn) {
        return function() {
            fn.apply(target, arguments);
        }
    },
    addEvent: function(type, listener) {
        if (this.addEventListener) {
            this.addEventListener(type, listener, false);
        } else {
            this.attachEvent('on' + type, listener);
        }
    },

    removeEvent: function(type, listener) {
        if(this.removeEventListener) {
            this.removeEventListener(type, listener, false);
        }
        else {
            this.detachEvent('on' + type, listener);
        }
    },

    getEventPoint:function(event) {
        var evt = event || window.event;
        this.item.innerHTML = evt.clientX + ":" + evt.clientY;

    }
}
window.onload = function() {
    var obj = document.getElementById('test');
    myobj.init(obj);
}</script>
</head>
<body>
    <div id="test" style="width:400px; height:300px; border-style:solid; border-width:1px; background-color:#ffffff"></div>
</body>
</html>1.为什么this.addEvent这种自带的方法也要apply
2.为什么this.addEvent会用this来引用
3.你代码习惯非常的不好啊
4.wrapper方法现在几乎可以用bind代替了