Integrate Analytics & Fix Redirect -- 2

My AJAX-driven site currently lacks proper visitor tracking and throws an error instead of redirecting customers after they complete checkout. I want these two issues resolved together.

1) Visitor analysis
• Integrate Google Analytics so every virtual page view on this single-page style interface is captured accurately. Dynamic URL changes triggered by AJAX must register as distinct page views without forcing full reloads. Please keep existing code lightweight and optimise any added snippets for performance.

2) Checkout redirect
• Diagnose and eliminate the error message that appears the moment an order is placed. The page should route customers seamlessly to the confirmed “/thank-you” URL (or whichever endpoint you find in the config) with no visible glitches. Front-end JavaScript and any server-side logic involved in the redirect need thorough testing after the fix.

Acceptance criteria
• Real-time GA dashboard shows each in-app navigation as a page view.
• A successful order ends in the correct confirmation page 100 % of the time, with no error pop-ups in console or UI.

Tech stack is plain JavaScript, jQuery, and PHP on the back end. Share a brief outline of your approach, estimated turnaround, and any previous SPA analytics experience when you submit.