js前端验证和绕过

一、js前端验证

本篇基于上篇，修改了form.html

 1 <!DOCTYPE html>
 2 <html lang="en">
 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>Document</title>
 8     
 9 </head>
10 <body>
11     <form method="POST" onsubmit="return check(this)">
12         {{info.string()}}
13         {{info.sub()}}
14     </form>
15     <script>
16         function check(f){
17             var str=f.string.value;
18             var c=new Array('script','<','>','input','img');
19             for(var i=0;i<c.length;i++){
20                 if(str.indexOf(c[i])!=-1){
21                     alert("存在敏感字符："+c[i]);
22                     return false;
23                 }
24             }
25             return true;
26         }
27     </script>
28 </body>
29 </html>