2014.01.27 笔记 JS 小考题

 

 

 

<script type="text/javascript" >
    function x() {
        alert(2);
    }
    x();
    var x = function () {
        alert(0);
    };
    x();
    var x = function () {
        alert(1);
    };
    x();
    function x() {
        alert(3);
    }
    x();
    //结果是弹出： 3 0 1 1
    
    ----------------------------------
    if (!("a" in window)) {
        var a = 1;
    }
    alert(a);//Rs: undefined
    
    ----------------------------------
    var a = 1,
     b = function a(x) {
         x && a(-xx);
     };
    alert(a);//Rs: 1
    ----------------------------------

    function a(x){ 
        return x*2; 
    }
    var a;
    alert(a);//Rs: function a(x){ return x*2;}

    ----------------------------------

    function b(x,y,a){ 
       arguments[2] = 10; 
       alert(a); 
     }
    b(1,2,3);//Rs: 10
    
    ----------------------------------

    function test(x){
        alert(x);
        var x = 123; 
        function x(){  
        }
        alert(x); 
    }
    test(222);//Rs: function x(){} ，123

    
    var obj = {  
      i : "test",  
      m : function(){  
         alert(this.i);//指向obj对象 ,值test  
         function B(){  
            var i = 1;  
             alert(this.i);//指向window对象,值undefined  
           }  
           B(); 
       }  
    }  
    obj.m();//Rs: test ， undefined

</script>