1. <pre name="code" class="js"><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">       
  2. <html xmlns="http://www.w3.org/1999/xhtml" >       
  3. <head>       
  4.     <title>无标题页</title>       
  5.     <style type="text/css">       
  6.         .code       
  7.         {       
  8.             background-p_w_picpath:url(code.jpg);       
  9.             font-family:Arial;       
  10.             font-style:italic;       
  11.             color:Red;       
  12.             border:0;       
  13.             padding:2px 3px;       
  14.             letter-spacing:3px;       
  15.             font-weight:bolder;       
  16.         }       
  17.         .unchanged       
  18.         {       
  19.             border:0;       
  20.         }       
  21.     </style>       
  22.     <script language="javascript" type="text/javascript">       
  23.            
  24.      var code ; //在全局 定义验证码       
  25.      function createCode()       
  26.      {        
  27.        code = "";       
  28.        var codeLength = 6;//验证码的长度       
  29.        var checkCode = document.getElementById("checkCode");       
  30.        var selectChar = new Array(0,1,2,3,4,5,6,7,8,9,'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z');// 所有候选组成验证码的字符，当然也可以用中文的       
  31.                
  32.        for(var i=0;i<codeLength;i++)       
  33.        {       
  34.              
  35.                
  36.        var charIndex = Math.floor(Math.random()*36);       
  37.        code +=selectChar[charIndex];       
  38.               
  39.               
  40.        }       
  41. //       alert(code);       
  42.        if(checkCode)       
  43.        {       
  44.          checkCode.className="code";       
  45.          checkCode.value = code;       
  46.        }       
  47.               
  48.      }       
  49.             
  50.       function validate ()       
  51.      {       
  52.        var inputCode = document.getElementById("input1").value;       
  53.        if(inputCode.length <=0)       
  54.        {       
  55.            alert("请输入验证码！");       
  56.        }       
  57.        else if(inputCode != code )       
  58.        {       
  59.           alert("验证码输入错误！");       
  60.           createCode();//刷新验证码       
  61.        }       
  62.        else       
  63.        {       
  64.          alert("^-^ OK");       
  65.        }       
  66.               
  67.        }       
  68.               
  69.     </script>       
  70. </head>       
  71. <body onload="createCode()">       
  72. <form  action="#">       
  73.      <input  type="text"   id="input1" />       
  74.     <input type="text" onclick="createCode()" readonly="readonly" id="checkCode" class="unchanged" style="width: 80px"  /><br />       
  75.     <input id="Button1"  onclick="validate();" type="button" value="确定" />        
  76. </form>       
  77. </body>       
  78. </html></pre>