Problem with special characters and quotes

Hi everyone

Before I begin, please excuse my bad english,I'm french :p
So, I have a problem using fckeditor.

First, I'll try to explain my application.

I'm using fckeditor in a ajax application.
I have my page, with the fckeditor, which call a javascript function (ajax) when I'm cliking on a button.
Then my ajax function reload one part of my page by calling a php page, which treat the data of the editor, passed to the page with a POST method (Am I clear?? :s)

I have a lot of problem when I'm using some special characters like quotes, doublequotes or "é", "è", etc....

When I'm looking at the data of the editor, in my php page, before saving it in a database, the data is cut where there is a special character. Everything after this character disapear.
I really don't know how to solve the problem. Please, can someone help me?? Do I have to put some functions in my javascript, or in my php??

Thanks for helping me !