How can I allow only HTML into my database?

Question

I'm trying to allow the user to input only HTML into a form, and on submit, store it into the database. I've been trying to use mysql_real_escape_string , but the PHP I put into the form with the HTML tags seems to not be stripped. How can I "filter" what is stored into the database?

EDIT:
I want to keep the HTML as-is. So, say a user inputs

<input type="text"/>

and hits submit; I want that to be entered into the database without any problems, and then later on down the road, be able to show up on their post.

I want to get rid of things such as PHP tags:

<input type="text"/>
<?php echo "Hello World!"; ?> <-- I do not want to store this.

If it's still not making any sense I will try my best to explain it a little better.

Answer 1

You'll need to parse the HTML and strip out unwanted tags. This is a relatively trivial with a decent parser, such as the PHP XML Parser .