How to dynamically link the title of the article and the menu on the site?

Question

JavaScript

On the left there is a menu in the form of a list of sections. The user selects the desired section, then the list of subsections leaves - the menu expands down. The user selects subsection #2, the content of the page on the right changes - the list of subtopics 2.1, 2.2, 2.3 of the selected subsection #2 and the title of the first article, as well as the article itself, are loaded into it. Then you can go to different subtopics 2.1, 2.2, 2.3
Server side questions.
1. If the user found an article (subtopic) 2.2 through a search engine, googled it and immediately got to the page with subtopic 2.2, it is necessary for him to immediately see the selected section, the list of subsections (which, during normal use of the site, leaves when you click on the section). And a glowing sub-theme. I'll try to simplify the explanation - that is, the user who found the article through Google did not select / click anything on the site, but everything on the page was already selected for him. He sees the selected section, an expanded list of subsections to which the article belongs - even though he did not select anything. How can this be arranged? I will be very grateful for the hint.
2. Newbie questions is a song)) And yet, what is better for site performance? I want to make XHR requests, after which the articles on the right side of the site will be updated. Am I thinking in the right direction? Maybe there are some features that need to be taken into account and XHR is not the best idea, if so, what would you advise?

Answer 1

We define the request - where did
/search?q=tramp
come from ? (if desired, the form itself is reloaded),
the form, when opening the site for the word tramp, makes the necessary request and displays the results through Ajax.
Whether it's a menu or something.