How to Set a Minimum Character Limit on an HTML Textarea?

You can use the minlength attribute (which is very well-supported across different browsers) on the HTML <textarea> element to enforce minimum number of characters that a user must enter for the input to be valid. For example:

<textarea minlength="3"></textarea>

This would limit a <textarea> element to a minimum of 3 (UTF-16 code units) characters.

For a more visual example, you could try the following HTML/CSS code:

<style>
textarea:invalid { border: 1px solid red; outline: none; }
</style>

<textarea minlength="3" required></textarea>

This would turn the border of the <textarea> element red, as long as the input is invalid/empty.

Please note that if no minlength is set on the <textarea> element, or a non-positive integer value is set, then no minimum input is enforced.