js36---函数嵌套 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <script type=text/javascript charset=utf-8>
        function F(){
            alert("函数F")
            var a= 1;
            return function(){
                this.name = a++;
                alert(this.name);
            }
        }
        var f1 = F();//    函数F
        f1();//1
        f1();//2

        var f2 = F();//    函数F
        f2();//1
        f2();//2    

        var f3 = F();//    函数F
        var f31 = new f3();//1
        alert(f31.name);//1
        var f32 = new f3();//2
        alert(f32.name);//2
//------------------------------------------------
        var f4 = new F();//    函数F
        f4();//1
        f4();//2

        var f5 = new F();//    函数F
        f5();//1
        f5();//2

        var f6 = new F();//函数F
        var f61 = new f6();//1
        alert(f61.name);//1
        var f62 = new f6();//2
        alert(f62.name);//2
        </script>
    </head>
    <body>
    </body>
</html>

外层函数既可以当成函数看也可以当成类看。内部返回的既可以当成函数看也可以当成类看。

var getXHR = function(){
             alert(2);
             getXHR = function(){
                alert(1);    
             }
        }
        getXHR();//2
        getXHR();//1
        getXHR();//1
 

        var getXHR = function(){
             var a  = 1; 
             getXHR = function(){
                return 2;    
             }
            return a;
        }
        alert(getXHR());//1
        alert(getXHR());//2
        alert(getXHR());//2
 

var getXHR = function(){
             var a  = 1; 
             getXHR = function(){
                alert(2);
                return 2;     //只是return了内部函数
             }
            getXHR();
            return a;
        }
        alert(getXHR());//2   1
        var getXHR = function(){
             var a  = 1; 
             getXHR = function(){
                alert(2);
                return 2;    
             }
            (function(){ //不能这么写
                alert(3);
                return 2;    
             })();  // is not a function
            getXHR();
            return a;
        }
        alert(getXHR());//2  1

 

function F(){}
    var f = function(){}
    
    Function.prototype.method =function(name,fn){
        alert(1);
    }
    f.method();//1
    F.method();//1
 

function F(){}
    var f = function(){}
    
    Function.prototype.method =function(name,fn){
        this.prototype[name] = fn;
        return this;
    }
    f.method("a",function(){alert("a");});//1
    F.method("b",function(){alert("b");});//1

    //f.a();//f.a is not a function
    f.prototype.a();//a
    //F.b();//F.b is not a function
    F.prototype.b()//b
    new F().b();//b

 

posted @ 2017-05-22 18:35  无天666  阅读(983)  评论(0)  编辑  收藏  举报