javascript實現的驗證碼程式碼例項

admin發表於2017-03-08
JavaScript

驗證碼大家應該不陌生，主要是為了網站的安全性，防止惡意註冊和登陸。驗證碼實現的方式各有不同，下面是一段用javascript實現的驗證碼效果，供大家參考之用，希望能夠給大家帶來幫助。

程式碼如下:

[HTML] 純文字檢視 複製程式碼
<!DOCTYPE html>
<html>
<head>
<meta charset=" utf-8">
<meta name="author" content="http://www.softwhy.com/" />
<title>螞蟻部落</title>
<style type="text/css">
.code {
  background:url(code_bg.jpg);
  font-family:Arial;
  font-style:italic;
  color:blue;
  font-size:30px;
  border:0;
  padding:2px 3px;
  letter-spacing:3px;
  font-weight:bolder;
  float:left;
  cursor:pointer;
  width:150px;
  height:60px;
  line-height:60px;
  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 = 6; //驗證碼的長度
  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'); //所有候選組成驗證碼的字元，當然也可以用中文的
  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("請輸入驗證碼！");
  }
  else if(inputCode.toUpperCase() != code.toUpperCase()) {
     alert("驗證碼輸入有誤！");
     createCode();
  }
  else {
    alert("驗證碼正確！");
  }        
}    
</script>
</head>
<body onload="createCode()">
<form id="form1" runat="server" onsubmit="validateCode()">
  <div>
    <table border="0" cellspacing="5" cellpadding="5" >
      <tr>
        <td></td>
        <td><div class="code" id="checkCode" onclick="createCode()" ></div></td>
        <td><a  href="#" onclick="createCode()">看不清換一張</a></td>
      </tr>
      <tr>
        <td>驗證碼：</td>
        <td><input  style="float:left;" type="text"   id="inputCode" /></td>
        <td>請輸入驗證碼</td>
      </tr>
      <tr>
        <td></td>
        <td><input id="Button1"  onclick="validateCode();" type="button" value="確定" /></td>
        <td></td>
      </tr>
    </table>
  </div>
</form>
</body>
</html>

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