HTML:lframe-inf on a mac

So I’m terrible with computers… Avast keeps popping up on every website I visit saying that a threat has been blocked. I’m really not sure how to remove this on a mac. (If anyone answers, please keep in mind I know absolutely nothing about computers).
Thanks in advance.

Edit: Whoops, this might be helpful. I just downloaded Avast today and this starts happening about thirty minutes afterwards. Also, I don’t know how to post screenshots, but I have one of the warning that pops up. It says the process is /Applications/Google Chrome.app/Contents/MacOS/Google Chrome and the file is /Users/jennypas/Library/Caches/Google/Chrome/Default/Cache/data_4
…I can’t even find the file in question. Completely confused.