javascript实现登录验证码

时间：2021-05-11 12:35:38

1.js

var code="" ; //在全局 定义验证码

function createCode(){

code = "";

var codeLength = ;//验证码的长度

var checkCode = document.getElementById("checkCode");

checkCode.value = "";

var selectChar = new Array(,,,,,,,,,,'A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z');

for(var i=;i<codeLength;i++) {

   var charIndex = Math.floor(Math.random()*);

   code +=selectChar[charIndex];

}

if(code.length != codeLength){

   createCode();

}

document.getElementById("checkCode").innerHTML = code;

}

function validate () {

var inputCode = document.getElementById("checkNum").value.toUpperCase();

if(inputCode.length <=) {

   alert("请输入验证码！");

   return false;

}

else if(inputCode != code ){

   alert("验证码输入错误！");

   createCode();

   return false;

}

else {

   alert("验证码通过！");

   return true;

}

}

2.html

 <body onload="createCode();">
<input type="text" value="" id="checkNum" />

<a id="checkCode" onclick="createCode()"></a>

<input type="button" class="btnCheck" id="gotoCheck"  value="验证"  onclick="validate();" />

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