How to style form validation in Drupal?

Question

AJAX

In form validation, there is such a wonderful function drupal_set_message, which displays an error message, displaying text for an incorrect field. But what if I want to go and change the style of this field so that it is highlighted in red? In other words, how to change the style of the field with an error?

Answer 1

It looks like your test page is returning the result in JSON, not HTML.

Answer 2

Apparently, if you want to insert the content of the test page, then you need to write test.html (well, or whatever extension you need). And in this form ('/test/') looks like the path to the folder test.