Weird thing happened.

Question

I was testing out, "_Text", but then I erased everything exept for "<" (at the front), I put a letter after it, and it disappears. This only happens when you are editing question/answer, when you click "save changes", the words/letters become visible. Why does this happen?

Answer 1

It's just HTML. The browser will try to parse things starting with a less than sign (<) and with text after it as HTML since that's what those kind of tags look like.
That will make it seem like it's "disappearing" since HTML tags aren't meant to be displayed as they're written but converted to something that'll have some meaning in terms of making websites. :)
The reason it's only happening in answers is because I guess comments aren't allowing anything like that inside of them.