script type="text/javascript"> /* function say(name,age){     alert(name+"今年"+age+"岁了"); } say("张三",3); */  var sayFunc=new Function("name","age","alert(name+‘今年‘+age+‘岁了‘)"); sayFunc("李四",4); </script><script type="text/javascript"> var sayFunc=new Function("name","age","alert(name+‘今年‘+age+‘岁了‘)"); // sayFunc("李四",4); alert("sayFunc方法对象的方法参数个数："+sayFunc.length); </script><script type="text/javascript"> var sayFunc=new Function("name","age","alert(name+‘今年‘+age+‘岁了‘)"); // sayFunc("李四",4); // alert("sayFunc方法对象的方法参数个数："+sayFunc.length); alert(sayFunc.toString()); alert(sayFunc.valueOf());</script>

//全局变量<script type="text/javascript">    var a=22;        function func(){        alert(a);    }        func();</script>//这样可以访问，不写var说明a也是一个全局变量<script type="text/javascript">    function func(){        // var a=22;        a=22;    }        func();    alert(a);    </script>//函数外面能访问局部变量，是通过func2实现的，func2就是所谓的闭包<script type="text/javascript">    function func(){        var a=22;                function func2(){            return a;        }                return func2;    }        var result=func();    alert("访问func的私有局部变量a:"+result());    </script>//键值对的写法<script type="text/javascript">    var name="The Window";    var object={            name:"My object",            getNameFunc:function(){                return function(){                    return this.name;                };            }    };    alert(object.name);    alert(object.getNameFunc()());</script>//JS面向对象<script type="text/javascript">    var marry={        name:"marry",        age:2,        shout:function(){            alert("我是："+this.name+",今年："+this.age);        },        action:function(){            alert("会吃");        }    };        alert(marry.name);    alert(marry.age);    marry.shout();    marry.action();        function Dog(name,age){        this.name=name;        this.age=age;        this.shout=function(){            alert("我是："+this.name+",今年："+this.age);        };        this.action=function(){            alert("会吃");        };    }        var jack=new Dog("jack",1);    alert(jack.name);    alert(jack.age);    jack.shout();    jack.action();</script>//对象属性，私有属性，类属性<script type="text/javascript">    function C(){        this.objPro="对象属性";        C.prototype.objPro2="对象属性2";        var privatePro="私有属性";    }    C.classPro="类属性";        alert(C.classPro);    var c=new C();    alert(c.objPro);    alert(c.objPro2);</script>////对象方法，私有方法，类方法<script type="text/javascript">    function C(){        var privateFunc=function(){            alert("私有方法");        };        privateFunc();        this.objFunc=function(){            alert("对象方法");        };        C.prototype.objFunc2=function(){            alert("对象方法2");        };    }    C.classFunc=function(){        alert("类方法");    };        C.classFunc();    var c=new C();    c.objFunc();    c.objFunc2();</script>//JS的继承1---用apply实现属性和方法的继承<script type="text/javascript">    function Animal(name,age){        this.name=name;        this.age=age;        this.shout=function(){            alert("我是："+this.name+",今年："+this.age);        };        this.action=function(){            alert("会吃");        };    }        function Dog(name,age){        Animal.apply(this, [name,age]);    }        var jack=new Dog("jack",1);    alert(jack.name);    alert(jack.age);    jack.shout();    jack.action();</script>//JS继承2---prototype原型的继承<script type="text/javascript">    function Animal(name,age){        this.name=name;        this.age=age;        this.shout=function(){            alert("我是："+this.name+",今年："+this.age);        };        this.action=function(){            alert("会吃");        };    }        function Dog(name,age){        Animal.apply(this, [name,age]);    }    Dog.prototype=new Animal();        var jack=new Dog("jack",1);    alert(jack.name);    alert(jack.age);    jack.shout();    jack.action();</script>//JS多态<script type="text/javascript">    function Animal(){        this.say=function(){            alert("我是动物");        };    }        function Dog(){        this.say=function(){            alert("我是狗");        };    }    Dog.prototype=new Animal();        function Cat(){        this.say=function(){            alert("我是猫");        };    }    Cat.prototype=new Animal();        function say(animal){        if(animal instanceof Animal){            animal.say();        }    }        var dog=new Dog();    var cat=new Cat();    say(dog);    say(cat);</script>