Sorry for double posting the same topic, but I don't know is it WP error or I missed something in template.
I was testing my first template and I discovered that I can leave comments with every html tag (I've checked this on low level account, every user can put some strange code like </div><div style="position: absolute; width: 100%; height: 100%; background: #000; color: #fff;">Buahahaha! I don't like you!</div>)
I don't know if there is either error in the template or in WordPress code. That's my first layout and I may missed something important (any code lines? I've based it on one of the templates - I left all the php code and put there my template)