jQuery element reloader
Sorry I was busier earlier. Here is a more complete review. Just a few things off the top of my head.


Try and be consistent with your class naming. Instead of  .js_container-reloader and js_reload-container use a common prefix, i.e. .js_reloader-trigger (or even just .js_reloader) and .js_reloader-container
You can use a single call to the on function like: 

$(document).on("submit", ".js_container-reloader", ...
var element = $(element), is syntactically incorrect since element is already defined as a parameter. One options is just use element = $(element);  another pattern I often see is using a $ prefix on variables to indicate jQuery objects, i.e. var $element = $(element),
requestUrl = element.attr('action'); would be better asrequestUrl = element.prop('action'); the latter will retrieve the default method for the form if no attribute is set.
I personally think the use of wrap andunwrap` is an odd way to handle adding an element. I would remove the wrap and container code and just have something like the following on success:

success: function(result){
   ....
   element.after(result);
   element.remove();

I would add a .js_reloader-loading class to the element before starting the ajax query so that you can style it differently (fade it, add a spinner, etc). 
Lastly you probably want to implement some kind of logic to prevent multiple attempts at loading the form.