1 <html lang="en">
 2 
 3 <head>
 4     <meta charset="UTF-8">
 5     <meta name="viewport" content="width=device-width, initial-scale=1.0">
 6     <meta http-equiv="X-UA-Compatible" content="ie=edge">
 7     <title>排他思想</title>
 8 </head>
 9 
10 <body>
11     <button>按钮1</button>
12     <button>按钮2</button>
13     <button>按钮3</button>
14     <button>按钮4</button>
15     <button>按钮5</button>
16     <button>按钮6</button>
17     <script>
18         // this  self  指针
19         window.onload = function() {
20             var btns = document.querySelectorAll("button");
21             for (var i = 0; i < btns.length; i++) {
22                 //   btns[i].index = i
23                 //   btns[i].onclick = function() {
24                 //       alert("你点击" + this.index + "的几个按钮");
25                 //   }
26                 //用闭包来做也可以
27                 (function(i) {
28                     btns[i].onclick = function() {
29                         alert("你点击" + i + "的几个按钮");
30                     }
31                 })(i)
32             }
33 
34         }
35     </script>
36 
37 </body>
38 
39 </html>