JavaScript高级篇之Function对象

JavaScript高级篇之Function对象

一： Function对象引入：

Function对象是js的方法对象，可以用Function实例化出任何js方法对象。

例如：

 <%@ page language="java" contentType="text/html; charset=utf-8"
     pageEncoding="utf-8"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 <title>JS</title>
 </head>
 <script type="text/javascript">
10 function say(name,age){
11     alert(name+"今年"+age+"岁了！");
12 }
13 say("张三","18");
 </script>
 <body>
 </body>
 </html>

二  用Function创建方法对象：

 <script type="text/javascript">
  var sayFun=new Function("name","age","alert(name+'今年'+age+'岁了！')");
   sayFun("李四","四");
 </script>

三 Function 对象属性：

 <script type="text/javascript">
  var sayFun=new Function("name","age","alert(name+'今年'+age+'岁了！')");
  alert("sayFun方法的参数个数为"+sayFun.length);
 </script>

四  Function对象方法：

 <script type="text/javascript">
  var sayFun=new Function("name","age","alert(name+'今年'+age+'岁了！')");
  alert(sayFun.toString());//Function仍然具有object对象的方法！
 </script>

效果一样！！

 <script type="text/javascript">
  var sayFun=new Function("name","age","alert(name+'今年'+age+'岁了！')");
 alert(sayFun.valueOf());//Function仍然具有object对象的方法！
 </script>