Hi, I'm encountering a lot of lag in Firefox. Websites are loading incredibly slow, mostly after the information actually loads. I'm looking for an option to disconnect access to the internet for a webpage.

For example, Linkedin is the main contributor of this lag. It loads the visual webpage I see, then it loads a lot of information in the background. Until it finishes this background loading, I can't select any text. I'm looking for the option to stop this background loading. Something "stronger" than the button in the top left, where the refresh button is. I want to stop the webpage from being able to access the internet, is this possible?