i get undefiend when i use selector inside ajax code code example

Example 1: qjuery

jQuery is a JavaScript library designed to simplify HTML DOM tree
traversal and manipulation, as well as event handling, CSS animation,
and Ajax.

It is free, open-source software using the permissive MIT License.

As of May 2019, jQuery is used by 73% of the 10 million most popular
websites

Example 2: jquery OR operation

$('[myc="blue"],[myid="1"],[myid="3"]');