数字验证码

首先在html中引入之前封装好的css样式和js文件

<script type="text/javascript" src="res/js/code.js"></script>

<link rel="stylesheet" type="text/css" href="res/css/code.css">

<!-- readonly="readonly 只读 -->   

验证码：<input  id="input1" style="width: 80px;" />   

<input id="checkCode" class="code" style="width: 55px" readonly="readonly" /> <a href="#"  onclick="createCode()" style="color: red">看不清，换一张</a> 

function中写这些

var inputCode = document.getElementById("input1").value.toUpperCase();      
var codeToUp=code.toUpperCase();  
if(inputCode.length <=0) {      
 alert("请输入验证码！");      
 return false;      
}      
else if(inputCode != codeToUp ){      
  alert("验证码输入错误！");      
  createCode();      
  return false;      

var code ; //在全局 定义验证码      function createCode(){       code = "";      var codeLength = 4;//验证码的长度      var checkCode = document.getElementById("checkCode");      checkCode.value = "";      var selectChar = new Array(1,2,3,4,5,6,7,8,9,'a','b','c','d','e','f','g','h','j','k','l','m','n','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z');            for(var i=0;i
.code{      background-image:url(w1.jpg);      font-family:Arial;      font-style:italic;      color:#000;      border:0;      padding:2px 3px;      letter-spacing:3px;      font-weight:bolder;      } 

}  ;