Forum vs. "Normal" HTML

[jessmanboo22]

I made this post when I was around 12 years old and didn't know anything about computer science, web design, or any of those kinds of things.

blaaaaaaaattt

[Vehek]

Does this help you?
http://en.wikipedia.org/wiki/BBCode

[V_Translanka]

If you want to show board tags, just do this...

[*img]http://www.outregallery.com/images/products/dont_be_stupid.jpg[/img]

The asterisk will stop them from being implemented...and it doesn't look all lame like spelling out "brackets" & such...

[Ramsus]

Hello y'all

I really wonder... I get annoyed when I just finished learning all the HTML I could possibly learn, and then you go to a forum and there's a completely new set of tags that have to be used!
I hope you don't get the impression that I'm complaing; rather, I guess I'm asking if anyone knows why Forum HTML's seem to be so different from Webpage HTML's.

For example, tags have to go in brackets instead of carets, and url's are put like the following (words in bold indicate the symbol they name)

bracketurlbracketyour url herebracket/urlbracket, rather then something like carot"a href=your url here"carotYour text herecarot/acarot

Does anyone know why forum HTML is different?

EDIT: Oops, sorry, all those red backgrounds are kind of ye straining... here, I just changed it to bold  .

Cross-site scripting attacks. That's the reason we don't simply allow HTML in posts. You have to sanitize inputs, and it's much safer to simply disallow HTML tags. Even BBCode can be implemented with serious vulnerabilities if you simply convert them to HTML tags or toss their values into HTML tags and attributes without sanitizing them first...

[Jutty]

If you know html then you should have no problem reading and understanding how to use BBcodes.