<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title> <!--楊艷文38號-->
<script type="text/JavaScript">
function checkUser(){
var uname = document.querySelector("#un").value;
var len = uname.length;
var ino = uname.toLowercase.indexOf('admin');
if(len<3||len>30||ino!=-1){
alert("用戶名不合法!");
return false;
}
return true;
}
</script>
</head>
<body>
<form action="ok.html" method="post" onsubmit="return checkUser();">
用戶名：<input type="text" id="un">
<input type="submit" value="https://bbs.csdn.net/topics/注冊">
</form>
</body>
</html>
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標籤：JavaScript