JS实现随机生成验证码

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本文实例为大家分享了JS实现随机生成验证码的具体代码，供大家参考，具体内容如下

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8" />
  <title></title>
  <style>   
  </style>
 </head>
 <body>
  <div>
  <h1>111111</h1><a href="#" rel="external nofollow" >看不清换一张</a>
  </div>
  验证码：<input type="text" value="" />
  <button>确定</button>
 </body>
 <script>
  var arr = ["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",
       0,1,2,3,4,5,6,7,8,9];
        var h1=document.querySelector("h1");
        var btn=document.querySelector("button");
        var change=document.querySelector("a");     
        var input=document.querySelector("input");         
         function fn(){
        var arr1=Math.floor(Math.random()*62);
        var arr2=Math.floor(Math.random()*62);
        var arr3=Math.floor(Math.random()*62);
        var arr4=Math.floor(Math.random()*62);
        var arr5=Math.floor(Math.random()*62);
        var arr6=Math.floor(Math.random()*62);
        var yz=""+arr[arr1]+arr[arr2]+arr[arr3]+arr[arr4]+arr[arr5]+arr[arr6];
            h1.innerHTML=yz;    
            btn.onclick=function(){
              alert(input.value);
             if(input.value==yz){
            alert("正确");
            }else{
             alert("错误");
            }
           
            }
         }
        fn();
    change.addEventListener("click",fn);
 </script>
</html>

1、Math.floor(）方法

Math.floor(x）

floor() 方法返回小于等于x的最大整数。

如果传递的参数是一个整数，该值不变。

2、Math.random()方法

random() 方法可返回介于 0（包含） ~ 1（不包含）之间的一个随机数。

使用以上两种方法可以实现取随机数的功能

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持极客世界。