In your load_media_type function you're sure that this code is returning the correct html (your last snippet of html)?
$('#select_media').load('{% url mem_media_type %}', '', function() {
$('#media_load').hide();
media_type();
});
There's far too much code to read there. But skimming through the description and the subsequent comment, it sounds like you are loading some HTML dynamically, and expecting a pre-existing click event to work on the newly-loaded HTML.
That doesn't work. Either you'll need to assign the click function specifically after loading the HTML, or use jQuery's live method to ensure that all added HTML inherits the function.