I have div.contentArea that contains some contents with scrollbar. It was defined that when the mouse enters div.content , return ID of the content and some more ajax action with this jQuery code:
$('.contentAarea').on('mouseenter','.content',function(){
    var getId = $(this).attr('id');
    alert(getId);
    // some more ajax actions.
}); 
for more details: http://jsfiddle.net/mr_mohsen_rasouli/4Nb9L/10/
now i define a div.mark element with fixed position and want when I scroll or up down and a div.mark enter the div.content , do action. 
How can I do that?
 
    