Contact form limit characters

For anyone who wants to limit the number of characters the contact form allows (e.g. you only want to receive short messages) here’s what you need to do.

Make a child theme, and duplicate front-page.php
Go to line 339 and add a max length attribute to the text area.
<textarea maxlength="500" etc.
The 500 means 500 characters, change it to what you like.