Clear intervals test page

This page attempts to clear all intervals with an intervalID from 1 to 1000 (inclusive). It’s used to demonstrate the issue of websites clearing the intervals set by extension content scripts. Install the demo Chrome extension and open the page console. You should see that the “Interval…” messages the extension intends to log aren’t displayed, since the website has cleared its interval. If you navigate to other pages under testpages.kzar.co.uk you should see the messages being logged. See https://crbug.com/860320.