When you reached this page through the WordPress dashboard then there is likely a problem with buttons or layouts not looking or working properly. This article explains the reason behind it and how to fix it.
Options looking odd
It is likely that with this error, options just look odd, but should work properly. For example, select buttons might look like this
Reason A: multiple calls to jQuery
The reason for such issues is likely the double inclusion of the jQuery library or some sub-libraries.
WordPress itself includes the jQuery library already. Unfortunately, some themes or plugins also load it. Loading it twice is likely to break any code that relies on it.
For example, this might be the order of jQuery files being included in the header of the site:
- jquery.js //wordpress core
- jquery-migrate.min.js //wordpress core
- jquery/ui/core.min.js //wordpress core
- jquery/ui/widget.min.js //wordpress core
- jquery-1.12.1.js // CUSTOM JS, loaded by plugin or theme. Overrides 1, 2, 3, 4
- jquery/ui/accordion.min.js //wordpress core. Error, 3 and 4 not found
- jquery/ui/button.min.js //wordpress core. Error, 3 and 4 not found
- jquery/ui/tooltip.min.js //wordpress core. Error, 3 and 4 not found
Number 5 is a duplicate inclusion of the jQuery library, which causes issues with the following library files.
Reason B: bootstrap.js
Similar to jQuery.js, your theme or another plugin might also use the bootstrap.js library. While using your own copy of the jQuery library is a sin, bootstrap.js is not included in the WordPress core. It just conflicts with some scripts in Advanced Ads. There is not much you can do about it. In best case, the backend still works despite the layout issue.
Troubleshooting 1: identify the cause
If you are less technical savvy you can just change your theme to see if it works with another theme. If that doesn’t solve your issue, you should test by switching off plugins one after the other.
Once you identified the theme or plugin that causes the issue you should reach out to its developer informing them about it. You can also link to this article to let them understand the issue.
Troubleshooting 2: fixing the issue
If you know your way around code and want to find out which theme or plugin causes the issue without disabling them, you should enable SCRIPT_DEBUG like described in step 2 here.
This allows you to see all included files in the source code of your page.
Search for any library that is included twice (starting with jquery.js itself) and check the path to the file to find the causing package.
To fix the issue yourself, you can use wp_dequeue_script() on the duplicate.