<!DOCTYPE html>
<html>
<head>
<title>html tutorial - html5 - html code - html form - In 30Sec by Microsoft Award MVP - | wikitechy required attribute</title>
</head>
<body>
<form action="#" onsubmit="alert('Submitted!');return false;">
<input type="text" name="username" required>
<input type="submit">
</form>
</body>
</html>
<html>
<head>
<title>html tutorial - html5 - html code - html form - In 30Sec by Microsoft Award MVP - | wikitechy required attribute</title>
</head>
<body>
<form action="#" onsubmit="alert('Submitted!');return false;">
<input type="text" name="username" required>
<input type="submit">
</form>
</body>
</html>
Result