system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do internet browsers fail to prevent "add extension" advert pages from locking up the browser?
gpt
There's lots of Javascript and HTML(5) APIs around that allow websites to provide cool content such as web apps and games. Sadly, since the authors of these APIs forget that there are evil developers around, they end up giving the APIs a lot of control over the browser that loads the page. 

This is also how some shady ads are capable of vibrating your phone, taking you to the app store, etc. Improper sandboxing and APIs with too much power.

You can reduce this by installing an Adblocker and NoScript, which makes pages incapable of doing much without your consent.