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Implementation of JavaScript login verification code

高洛峰Original: 2016-12-08 16:02:522108browse

Without further ado, the following two steps are needed to implement the js login verification code function. The specific implementation process is as follows:

1.js

var code="" ; //在全局 定义验证码
function createCode(){
code = "";
var codeLength = 6;//验证码的长度
var checkCode = document.getElementById("checkCode");
checkCode.value = "";
var selectChar = 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;J&#39;,&#39;K&#39;,&#39;L&#39;,&#39;M&#39;,&#39;N&#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;);
for(var i=0;i<codeLength;i++) {
var charIndex = Math.floor(Math.random()*32);
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 <=0) {
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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