js生成验证码

时间：2021-02-23 03:48:48

<!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>验证码</title>
  <style type="text/css">
   #code
   {
    font-family:Arial;
    font-style:italic;
    font-weight:bold;
    border:0;
    letter-spacing:2px;
    color:blue;
   }
  </style>

</head>
<body>
  <div>
   <input type = "text" id = "input"/>
   <input type = "button" id="code" onclick="createCode()"/>
   <input type = "button" value = "验证" onclick = "validate()"/>
  </div>
</body>
</html>

<script>
   var code ;
   window.onload = function createCode(){
     code = "";
     var codeLength = 4;
     var checkCode = document.getElementById("code");
     var random = 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');
     for(var i = 0; i < codeLength; i++) {
     var index = Math.floor(Math.random()*36);
     code += random[index];
    }
    checkCode.value = code;
   }

   function validate(){
    var inputCode = document.getElementById("input").value.toUpperCase();
    if(inputCode.length <= 0) {
     alert("请输入验证码！");
    }
    else if(inputCode != code ) {
     alert("验证码输入错误！@_@");
     createCode();
     document.getElementById("input").value = "";
    }
    else {
     alert("^-^");
    }
   }
   </script>

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