How to import VBcode?

Ok. so, finally, after hours of swimming through Kirupa’s .js files, I already have my Javascript to enter the [-b] [-/b] tags. So, when they click on a B button, it automatically enters the tags.

Now, when I bring it from the database to be displayed in the PHP file. I see the [-b] tags, like:

[-b] hey! im supposed to be bolded, but i have this B’s instead [-b]

So, how to I make BBcode work?

Please forgive my ignorance. All I have learned it’s through online tutorials, reading books, or through you guys.