Getting coordinates from draggable_element

I tried to get the coordinates of a draggable_element.

I found in this topic a way to get the coordinates but i don't know what i must set in the action reposition

at the moment i only have this

<div id ="dragDIV" class ="picture box">Verplaats de afbeelding naar de gewenste plaats</div> <%= draggable_element :dragDIV, :snap => 10, :ghosting => true %>

<%= drop_receiving_element("dragDIV", :url => { :action => "reposition" }, :loading => visual_effect(:highlight), :update => 'admin_status_message', :with => "'id=' + encodeURIComponent(element.id) + '&x=' + encodeURIComponent(Element.getStyle(element,'left')) + '&y=' + encodeURIComponent(Element.getStyle(element,'top')) + '&w=' + encodeURIComponent(Element.getStyle(element,'width')) + '&h=' + encodeURIComponent(Element.getStyle(element,'height'))") %>