原型 

 1 <!doctype html>
 2 <html>
 3 <head>
 4 <meta charset="utf-8">
 5 <title></title>
 6 <style>
 7 
 8 </style>
 9 
10 </head>
11 <body>
12 
13 <script type="text/javascript">
14     var arr1 = new Array(12,55,34,78,676);
15     var arr2 = new Array(100,2,34,6,8);
16 
17     Array.prototype.sum = function()    //相当于class，给一组对象加方法
18     //arr1.sum = function()  //相当于行间样式，只给一个对象加方法
19     {
20         var result = 0;
21         for(var i=0;i<arr1.length;i++)
22         {
23             result += this[i];
24         }
25 
26         return result;
27     }
28     alert(arr1.sum());
29     alert(arr2.sum());
30 </script>
31 </body>
32 </html>

 

posted @ 2017-01-20 14:46  萤子  阅读(116)  评论(0)    收藏  举报