input pattern in html code example

Example 1: html input only letters

<!--To stop input from accepting numbers-->
<input onkeypress="return /[a-z]/i.test(event.key)" >

Example 2: html5 input pattern name

echo '<input type="text" maxlength="32" name="first_name" pattern="[A-Za-z]{1,32}" value="'.$_SESSION['user_first_name'].'" required>';