JavaScript怎样写网页上的验证码代码？

JCaliven 2010-02-26 06:11:03

用JavaScript如何写在浏览网业时要输入验证码的代码？如登陆用户时要输入验证码....... 请高手赐教！

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qqzeng-ip 2010-02-27

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >

<head>

    <title>无标题页</title>

    <style type="text/css">

        .code

        {

            background-image:url(code.jpg);

            font-family:Arial;

            font-style:italic;

            color:Red;

            border:0;

            padding:2px 3px;

            letter-spacing:3px;

            font-weight:bolder;

        }

        .unchanged

        {

            border:0;

        }

    </style>

    <script language="javascript" type="text/javascript">

    

     var code ; //在全局 定义验证码

     function createCode()

     { 

       code = "";

       var codeLength = 6;//验证码的长度

       var checkCode = document.getElementById("checkCode");

       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

        

       for(var i=0;i<codeLength;i++)

       {

      

        

       var charIndex = Math.floor(Math.random()*36);

       code +=selectChar[charIndex];

       

       

       }

//       alert(code);

       if(checkCode)

       {

         checkCode.className="code";

         checkCode.value = code;

       }

       

     }

     

      function validate ()

     {

       var inputCode = document.getElementById("input1").value;

       if(inputCode.length <=0)

       {

           alert("请输入验证码！");

       }

       else if(inputCode != code )

       {

          alert("验证码输入错误！");

          createCode();//刷新验证码

       }

       else

       {

         alert("^-^ OK");

       }

       

       }

       

    </script>

</head>

<body onload="createCode()">

<form  action="#">

     <input  type="text"   id="input1" />

    <input type="text" onclick="createCode()" readonly="readonly" id="checkCode" class="unchanged" style="width: 80px"  /><br />

    <input id="Button1"  onclick="validate();" type="button" value="确定" /> 

</form>

</body>

</html>