How do I create a form where a particular alphabet must be required , where a user must write that particular alphabet

Question

<form action="action_page.php">
<label for="fname">What color is the sky</label>
<input type="text" id="fname" name="firstname" placeholder="Skye color..." required>
</form>
Let’s say I want a user to type a particular alphabet, if a wrong alphabet is typed in the box if should show and error message

Answer 1

Hi kilisco1
you can use pattern with a regular expression
https://www.w3schools.com/tags/att_input_pattern.asp
which you can build here
http://html5pattern.com/