纯JS实现的验证码-可自定义长度和字符

江山如画 • 2018年10月9日下午2:55 • 网页制作 • 阅读 3239

纯JS实现的页面验证码-可自定义长度和验证码字符

生成验证码的函数

<script type="text/javascript">
var code;
function createCode() 
{
 code = "";
 var codeLength = 4; //验证码的长度
 var checkCode = document.getElementById("checkCode");
 var codeChars = 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',
      '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，可以用中文
 for(var i = 0; i < codeLength; i++) 
 {
  var charNum = Math.floor(Math.random() * 52);
  code += codeChars[charNum];
 }
 if(checkCode) 
 {
  checkCode.className = "code";
  checkCode.innerHTML = code;
 }
}
</script>

登录页面代码：

<body onload="createCode()">
<form id="form1" action="loginCheck.jsp" onsubmit="return validateCode()">
 <div>
  <table border="0" cellspacing="5" cellpadding="5" >
   <tr>
    <td>用户名：</td>
    <td><input type="text" name="username" id="username"></td>
    <td></td>
   </tr>
   <tr>
     <td>密　码：</td>
     <td><input type="text" name="pwd" id="pwd"></td>
     <td></td>
   </tr>
   <tr>
    <td>验证码：</td>
    <td><input style="float:left;" type="text"  id="inputCode" /></td>
    <td><div class="code" id="checkCode" onclick="createCode()" ></div><a href="#" onclick="createCode()">看不清换一张</a></td>
   </tr>
   <tr>
    <td></td>
    <td><input id="Button1"  type="submit" value="确定" /></td>
    <td></td>
   </tr>
  </table>
 </div>
</form>
</body>

检验验证码是否输入和输入是否正确的validateCode()函数代码：

function validateCode() 
{
 var inputCode=document.getElementById("inputCode").value;
 if(inputCode.length <= 0) 
 {
  alert("请输入验证码！");
  return false;
 }
 else if(inputCode.toUpperCase() != code.toUpperCase()) 
 {
   alert("验证码输入有误！");
   createCode();
   return false;
 }
 else 
 { 
  return true;
 }    
}

美化验证码CSS：

<style type="text/css">
.code 
{
 background:url(code_bg.jpg);
 font-family:Arial;
 font-style:italic;
 color:blue;
 font-size:18px;
 border:0;
 padding:2px 3px;
 letter-spacing:3px;
 font-weight:bolder;
 float:left;
 cursor:pointer;
 width:100px;
 height:18px;
 line-height:18px;
 text-align:center;
 vertical-align:middle;
}
a 
{
 text-decoration:none;
 font-size:12px;
 color:#288bc4;
}
a:hover 
{
 text-decoration:underline;
}
</style>

<!doctype html> <html> <head> <meta charset="utf-8"> <title>纯JS实现的验证码-可自定义长度和字符|www.125jz.com</title> </head> <body> <style type="text/css"> .code { background:url(code_bg.jpg); font-family:Arial; font-style:italic; color:blue; font-size:18px; border:0; padding:2px 3px; letter-spacing:3px; font-weight:bolder; float:left; cursor:pointer; width:100px; height:18px; line-height:18px; text-align:center; vertical-align:middle; } a { text-decoration:none; font-size:12px; color:#288bc4; } a:hover { text-decoration:underline; } </style> <script type="text/javascript"> var code; function createCode() { code = ""; var codeLength = 4; //验证码的长度 var checkCode = document.getElementById("checkCode"); var codeChars = 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','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 charNum = Math.floor(Math.random() * 52); code += codeChars[charNum]; } if(checkCode) { checkCode.className = "code"; checkCode.innerHTML = code; } } function validateCode() { var inputCode=document.getElementById("inputCode").value; if(inputCode.length <= 0) { alert("请输入验证码！"); return false; } else if(inputCode.toUpperCase() != code.toUpperCase()) { alert("验证码输入有误！"); createCode(); return false; } else { return true; } } </script> </head> <body onload="createCode()"> <form id="form1" action="loginCheck.jsp" onsubmit=" return validateCode()"> <div> <table border="0" cellspacing="5" cellpadding="5" > <tr> <td>用户名：</td> <td><label for="username"></label> <input type="text" name="username" id="username"></td> <td></td> </tr> <tr> <td>密　码：</td> <td><input type="text" name="pwd" id="pwd"></td> <td></td> </tr> <tr> <td>验证码：</td> <td><input style="float:left;" type="text" id="inputCode" /></td> <td><div class="code" id="checkCode" onclick="createCode()" ></div><a href="#" onclick="createCode()">看不清换一张</a></td> </tr> <tr> <td></td> <td><input id="Button1" type="submit" value="确定" /></td> <td></td> </tr> </table> </div> </form> </body> </html>

Tips:You can change the code before run.

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