serialize() after loading a form from PHP

serialize() after loading a form from PHP

Hello to the forum :-)
I am not very familiar with jquery so the first problems are not long in coming.

I am loading a form from PHP via ajax into a div container.
<div id = "" formdiv "> </div>
The form is displayed correctly, but the source code of the page does not show the html code of the form. (Only available in the cache?)
The form code is only accessible via $ ('# formdiv').html()
If the form is now to be sent to a serversite script, I need the values of the fields.
key_value = $ ('# formdiv').serialize() does not work.
key_value is allways empty.
Does somebody has any idea?

Thank you very much
Thomas