After doing a search (say for "wedding invitations"), and ending up on the search results page (like https://www.zazzle.com/s/wedding+invitations), the browser seems to be using a lot of CPU.

I've noticed this with Chrome, Firefox, and Safari on macOS.

This is what Chrome's built-in Task Manager shows for me, for example:


Is anyone else experiencing this?

It's a MacBook Pro Retina laptop, a few years old, running macOS 10.14.5.

It happens consistently with Chrome 76.0.3809.87, freshly opened. The default extensions from Google are disabled, and no others are installed.

Seems to happen for any search term I try that returns results. It happened for these result pages, for example:
https://www.zazzle.com/s/wedding+invitations
https://www.zazzle.com/s/birthday+cards
https://www.zazzle.com/s/personalized+hockey+pucks
https://www.zazzle.com/s/professional+business+cards

Like I mentioned before, it seems to happen with Safari and Firefox, too.

Steps to reproduce:
1. Open a modern web browser (like Chrome, Firefox, Safari)
2. Open https://www.zazzle.com/
3. Perform a search that returns results, and wait for the results page to finish loading.
4. Check Activity Monitor (macOS) for a browser process using significant CPU.
5. Close the Zazzle search results tab, and check that the CPU utilization has stopped.

For example, I see a "Google Chrome Helper (Renderer)" process consistently showing 100% or more CPU utilization in Activity Monitor on macOS while a Zazzle search results tab is open. Closing the tab stops the CPU usage.

With Firefox on macOS, the process is named "FirefoxCP Web Content", and is consistently showing 95% or more CPU utilization when a Zazzle search results tab is open.