You can always just create a new post and try and mess around in there without actually saving the post.
Yeah, you're right. Just preview it. I didn't really think of that, but you're absolutely correct about it!
I just updated my last post to also include DailyMotion videos, which can also be embedded in a similar manner. Some wise man showed me that yesterday :P
I was thinking that maybe I should update my presentation. Then I thought that it would probably be for the better to just make a new one and have a mod delete my old one (if mods delete threads, that is).