1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title></title>
6 </head>
7 <body>
8 </body>
9 <script type="text/javascript">
10 //一个函数运行结束以后它里面所有的变量会被编译器所收回
11 //简单的理解闭包：函数的嵌套
12 function fun1(){
13 var num1 = 10;
14 function fun2()
15 num1++;
16 console.log(num1);
17 return num1;
18 }
19 //var result = fun2;
20 //return result;
21 return fun2();
22 }
23 fun1();
24 </script>
25 </html>
26 </html>
原文：http://www.cnblogs.com/PowellZhao/p/5547106.html