javascript AOP 實現,ajax回呼函數使用比較方便

function actsAsDecorator(object) {  object.setupDecoratorFor = function(method) {    if (! ('original_' + method in object) ) {      object['original_' + method] = object[method];      object['before_' + method]   = [ ];      object['after_' + method]    = [ ];      object[method] = function() {        var i;        var b = this['before_' + method];        var a = this['after_'  + method];        var rv;        for (i = 0; i < b.length; i++) {          b[i].call(this, arguments);        }        rv = this['original_' + method].apply(this, arguments);        for (i = 0; i < a.length; i++) {          a[i].call(this, arguments);        }        return rv;      }    }  };  object.before = function(method, f) {    object.setupDecoratorFor(method);    object['before_' + method].unshift(f);  };  object.after = function(method, f) {    object.setupDecoratorFor(method);    object['after_' + method].push(f);  };}/**Invoking*/    function Test(){        this.say1 =  function(s){            alert(s);        }        this.say2 =  function(s){            alert(s);        }    }var t = new Test();actsAsDecorator(t);    t.before("say1",beforeHander);    t.after("say2",afterHander);    test();