regex input field code example
Example 1: html textbox pattern mobile number
<input type="text" name="Phone Number" pattern="[7-9]{1}[0-9]{9}"
title="Phone number with 7-9 and remaing 9 digit with 0-9">
Example 2: regex on input
<form>
<label for="username">Username <i>(letters and numbers only, no punctuation or special characters)</i></label><br>
<input name="username" id="username" pattern="[A-Za-z0-9]+">
</form>