JS功能来实现登陆验证码

浏览数：42 / 时间：2015年06月09日

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
#checkHR {
float:left;

}
#checkCode {
float:left;
width:90px;
height:15px;
padding: 0px 10px;
color:red;
font-size:16px;
font-family:Arial;
font-style:italic;
color:Red;
border:0;
padding:2px 3px;
letter-spacing:3px;
font-weight:bolder;
}
.refresh {
font-size: 14px;
color: red;
}
.text {
font-size: 16px;
color: #F00;
}
</style>
<script language="javascript" type="application/javascript">
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,‘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=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;
}

}
</script>
</head>

<body onload="createCode();" bgcolor="#33CCFF">
<table width="521" height="37" align="center">
<tr>
<td width="291"><div id="checkHR"><span class="text">请输入验证码：</span>
<input type="text" value="" id="checkNum" style="height:15px;"/></div></td>
<td width="101"><a href="javascript:void(0);"><div id="checkCode" onclick="createCode()";></div></a></td>
<td width="104"><input type="button" class="btnCheck" id="gotoCheck" value="验证" onclick="validate();" style="width:50px; height:25px; color:#39F;"/></td>
</tr>
</table>

</body>
</html>