how protect source html?

[bybruno]

hi,
i building a site of ads that can accept html source for users can show their ads with images with the custum sizes and with custum fonts and tables
flash content etc
but i want block some code like php code

< php>
include "ext";
<?>

and javascript too and other code that can result in a segurity issue.
there is any function in php or other way to detect that code before save to the db?
thanks a lot for your help
:)