Inserting a loading custom on the Ajax request

Summary:

I'm using a Ajax requisition on the my Agent Browser Web to my workspace contacts, and It is working fine .

Content (required):

But, when I try to insert a loading custom ( spinner ) before this requisition, it is not working, I can't to call $(.loader).show();

I try call in the console and it is not working as well.

Version (include the version you are using, if applicable):

The latest

Code Snippet (add any code snippets that support your topic, if applicable):

This is js file:

This is html file:

Other native functions like alert() is working.

Could you help me please?