How come my keyboard is acting weird?

My keyboard works fine when I am typing a Word Document. However, it sometimes acts up when I type into a search bar online. For some reason, some letters are omitted when the words show up on the screen, even though I know for sure I had typed those letters.

An example, let’s say I want to look up Rascal Flatts’s What Hurts the Most on Youtube. I would get back Rasl Ftts Wha Hus th Most on the search bar.

It’s really weird. This happens on Google and Wikipedia too. I was thinking it might have something to do with a plug-in or my internet connection, but I’m not sure if that’s right.