<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
form {
width: 200px;
margin: 20px auto;
}
form > div {
margin-bottom: 15px;
}
form > div > input {
display: block;
margin-bottom: 5px;
outline: none;
}
#txtID {
width: 150px;
}
#txtMessage {
width: 250px;
border: 0px solid transparent;
outline: none;
color: red;
}
</style>
<script>
var txtId, txtMessage;
function init() {
txtId = window.document.form1.txtId;
txtMessage = window.document.form1.txtMessage;
txtId.onkeyup = valid;
}
function valid() {
if (txtId.value.length == 0){
txtMessage.value = "";
} else if (txtId.value.length < 4) {
txtMessage.value = "아이디가 너무 짧습니다.";
} else if (txtId.value.length > 12) {
txtMessage.value = "아이디가 너무 깁니다.";
} else {
txtMessage.value = "아이디가 적합합니다.";
}
}
</script>
</head>
<body oncontextmenu='return false' ondragstart='return false' onselectstart='return false' onload='init();'>
<form name="form1">
<h1>회원 가입</h1>
<div>아이디 :
<input type="text" name="txtId" autofocus>
<input type="text" name="txtMessage" id="txtMessage">
</div>
</form>
</body>
</html>