Special characters issue

How are you passing the form data?

Once upon a time, for simple database queries based on only one value, I would append the variable to an Ajax $_GET URL.
Thus /controller/method/$variable would be /controller/method/qwe#rty.

This caused problems since anything after the '#' is not sent to the server, it is only used by the browser to link to DOM elements on that same URL.  Sending the Ajax request via $_POST solved it.