example 1


        var num1 = 5,
    num2 = 10,
    result = num1+++num2;

example 2


        var x = 5,
        o = {
            x: 10,
            doIt: function doIt(){
                var x = 20;
                setTimeout(function(){
                    alert(this.x);
                }, 10);
            }
        };
    o.doIt();

example 3


        var num1 = "10",
    num2 = "9";
    num1 < num2 的值是?
    +num1 < num2 的值是?
    num1 + num2 的值是?
    +num1 + num2 的值是?

example 4


        var message = "Hello world!";
    message.substring(1, 4)值是?
    message.substr(1,4)值是?

example 5


        var o = {
        x: 8,

        valueOf: function(){
            return this.x + 2;
        },
        toString: function(){
            return this.x.toString();
        }
    },
    result = o < "9";
    alert(o);
    result 的结果是？
    aler t打印的结果是？

example 6


           (function(){ 
          return typeof arguments;
        })();

example 7


            var f = function g(){ return 23; };
        typeof g();

example 8


        (function(x){
        delete x;
        return x;
    })(1);

example 9


        var y = 1, x = y = typeof x;
    x;

example 10


        (function f(f){ 
        return typeof f(); 
    })(function(){ return 1; });