I am writing a research paper that includes a comparison between two dynamic web apps. Namely, I want to compare the time it takes to accomplish a similar task on both of the apps. I know that one of the two is much more poorly optimized than the other, resulting in very poor page load speed, and I do not want that aspect to interfere with a UX experiment.
As such, I need to block the rendering of a website whose server I do not have access to until it's fully loaded and every resource has been fetched.
It doesn't really matter which browser, as long as it's capable of correctly displaying sites that are kind of modern. Is there any kind of plugin, script or other that I could attach to a browser that would accomplish this?