call小结

var Person1=  {name:"tom",say:function(){alert("my name is "+this.name);}}var Person2= {name:"cat",say:function(){alert("我是 "+this.name);}}Person1.say();//my name is tomPerson1.say.call(Person2);//my name is catvar empty ={};Person1.say.call(empty);//my name is undefined/*call说明：对象1.方法A.call(对象2)的作用是，让对象2替代本身对象1，如果对象1涉及的属性对象2不存在，则视为undeifend*/     <input type="text" id="myText"   value="将文本框作为对象">  <script>       function Obj(){this.value="Obj变量";}       var value="windows 全局 变量";       var Fun1={//全局的this为windowvalue:"内部方法全局变量", test:function(msg){alert(msg+":"+this.value);}}         Fun1.test("全局变量");   //内部方法全局变量    Fun1.test.call(window,"将window作为对象");  //windows 全局 变量      Fun1.test.call(document.getElementById('myText'),"将文本框作为对象");  //input text         Fun1.test.call(new Obj(),"将方法作为对象");   //Obj变量</script>