一、HTML代码
<html>
<head lang="en">
<meta charset="UTF-8">
<title>js验证码</title>
</head>
<!--onload="createCode()" 自动加载验证码的方法-->
<body onload="createCode()">
<div>
<div id="content" style="cursor: pointer" onclick="createCode()"></div>
<table border="1">
<tr>
<td>验证码：<input type="text" id="inputCode" /></td>
</tr>
<tr>
<td><input type="submit" value="确定" onclick="validateCode()"></td>
</tr>
</table>
</div>
</body>
</html>
二、JavaScript代码
<script type="text/javascript">
//定义验证码的全局变量
var code;
function createCode(){
code = "";
//验证码的长度
var codeLength = 4;
//验证码的组成字符范围
var codeChars = new Array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
'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');
for(var i = 0; i < codeLength; i++){
var charNum = Math.floor(Math.random() * 62);
code += codeChars[charNum];
}
//生成验证码
document.getElementById("content").innerHTML=code;
}
//表单提交事件
function validateCode() {
//用户输入的验证码
var inputCode=document.getElementById("inputCode").value;
if(inputCode.length <= 0) {
alert("请输入验证码！");
} else if(inputCode != code) {
alert("验证码输入有误！");
createCode();
} else {
alert("验证码正确！");
}
}
</script>