regex input validation code example

Example 1: name validation html

<input type="text" pattern="[a-zA-Z'-'\s]*">

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>