Detailed explanation of examples of implementing verification code function using JavaScript-JS Tutorial-php.cn

Detailed explanation of examples of implementing verification code function using JavaScript

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Release： 2017-04-21 09:56:32

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This article mainly introduces the relevant information on implementing the verification code function based on JavaScript

The example in this article shares the specific code for implementing the verification code in Javascript for your reference. The specific content is as follows

1. A simple example
New test.html

<!DOCTYPE html> 
<html>  
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<head>  
  <title>验证码</title>   
  <script src = "checkCode.js">  </script>  
</head>  
<body>  
  <p>  
    <input type = "text" id = "input"/>  
    <input type = "button" id="code" onclick="createCode()"/>  
    <input type = "button" value = "验证" onclick = "validate()"/>  
  </p>  
</body>  
</html>

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New checkCode.js

var code ; //在全局定义验证码   
 
window.onload = function createCode(){  
   code = "";   
   var codeLength = 4;//验证码的长度  
   var checkCode = document.getElementById("code");   
   var random = new Array(0,1,2,3,4,5,6,7,8,9,&#39;A&#39;,&#39;B&#39;,&#39;C&#39;,&#39;D&#39;,&#39;E&#39;,&#39;F&#39;,&#39;G&#39;,&#39;H&#39;,&#39;I&#39;,&#39;J&#39;,&#39;K&#39;,&#39;L&#39;,&#39;M&#39;,&#39;N&#39;,&#39;O&#39;,&#39;P&#39;,&#39;Q&#39;,&#39;R&#39;,  
   &#39;S&#39;,&#39;T&#39;,&#39;U&#39;,&#39;V&#39;,&#39;W&#39;,&#39;X&#39;,&#39;Y&#39;,&#39;Z&#39;);//随机数  
   for(var i = 0; i < codeLength; i++) {//循环操作  
    var index = Math.floor(Math.random()*36);//取得随机数的索引（0~35）  
    code += random[index];//根据索引取得随机数加到code上  
  }  
  checkCode.value = code;//把code值赋给验证码  
}  
//校验验证码  
function validate(){  
  var inputCode = document.getElementById("input").value.toUpperCase(); //取得输入的验证码并转化为大写     
  if(inputCode.length <= 0) { //若输入的验证码长度为0  
    alert("Empty Code!"); //则弹出请输入验证码  
  }      
  else if(inputCode != code ) { //若输入的验证码与产生的验证码不一致时  
    alert("Error Code"); //则弹出验证码输入错误  
    createCode();//刷新验证码  
    document.getElementById("input").value = "";//清空文本框  
  }      
  else { //输入正确时  
    alert("OK"); //弹出^-^  
  }        
}

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2. The position will not move when clicked Code:

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