Can't write < or >

I love CodeCademy, but I’ve avoided using it for anything that contains html since I can’t write < and > symbols.

Usually I type these symbols by pressing “Alt Gr + ,(comma)” or “Alt Gr +.(dot)”, but doing so on CodeCademy lesson causes the lesson to go “Back” or “Next”.

I use Croatian Keyboard Layout.
What’s causing this? Is there a way of avoiding it, apart from setting custom keyboard layout?