Ajax (most likely) functions stopped working in the wordpress admin panel. What to do?

Question

WordPress

There was a problem with the WordPress admin. When adding additional fields (namely, when clicking the "add" button), as well as when adding headings (when clicking on the add button), the page does not reload and changes are not visible. Only after refreshing the page, changes are visible (and in the case of a post and adding tags, you have to save it as a draft and open a new post). What to do? All file permissions are set correctly. This happened after the wp update most likely. Another blog on the same version of vp works great

Answer 1

the problem was in the theme's functions.php... I removed the extra line breaks at the bottom and everything worked. strange. I found a solution to the problem on some forum.

Answer 2

It was not ajax that stopped working for you, but jquery completely. It is strange that you do not complain about the work of animation on the page and similar elements. Check that in the page jquery is loaded once. You may have installed some plugin that redefines jquery. There may be problems accessing jquery. Try to give access rights to the directory where the library is located.
stackoverflow.com/questions/28241494/jquery-not-de...