initialize jquery with some js which require jquery

[chwzr]

i have added jquery in my header.php file under /usersc/includes

Code:

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

under this line i added a js library which depends on jquery loaded before.

Code:

<script type="text/javascript" src="/usersc/js/myUIlib.min.js"></script>

the error console says "$ is not defined"

since there are 3 reasons this error could have:

• 1. Your JavaScript file is not being properly loaded into your page
  
• 2. You have a botched version of jQuery. This could happen because someone edited the core file, or a plugin may have overwritten the $ variable.
  
• 3. You have JavaScript running before the page is fully loaded, and as such, before jQuery is fully loaded.
  

so i assume:

1. it is properly loaded as i can see in network analysis in firefox debug view
2. are there some plugins which override the $ variable?
3. i think my UIlib.min.js is loaded after jquery, i see it in network analysis so jquery should be finished before my UIlib.min.js is fired. or is there any other place to put those script?


i also see jquery is loaded twice? where is it loaded it should only loaded once in the header of the page(/usersc/includes/header.php) i think.

EDIT:

if i reference it in a blank content page both jquery and my myUIlib.js there are the same errors from the header, but on the page it is working. so what is wrong with the header ? is it loaded after the page content?