tugas

<!DOCTYPE html>
<html>
<meta charset=utf-8>
    <head>
        <title> cek validasi </title>
        <link href="css.css" rel="stylesheet" type="text/css">
<script>
function validasi_input(form){
  if (form.username.value == ""){
    alert("Mohon Isi Username!");
    form.username.focus();
    return (false);
  }
    if (form.password.value == ""){
    alert("Mohon Isi Password!");
    form.password.focus();
    return (false);
  }
return (true);
}
</script>
    </head>
<body>
<div id=body><h1><center>VALIDASI KOSONG</center></h1>
<div id=tengah>
<form method="get" action="#" onSubmit="return validasi_input(this)">
<p>Username : <input name="username" type="text"></p>
<p>Password : <input name="password" type="password"></p>
<p><input name="" type="submit" value="SUBMIT"></p>
</form></div>
</div>
</body>
</html>