Q: Sort an array relatively to one of his internal data in jQuery/Js Is there a way to specify in a sort() method a parameters that should be taken as reference?
For example : 
I have an array of element <li>...</li> which has in parameter the data : date = Wed Apr 20 2016 00:00:00 GMT+0200 (CEST) (for example).
Now let say I have multiple <li> with different date and I want those to be sort by chronological order. First I do an array with them. Then I try to sort them but I don't get how or even if it is possible to specify a parameter.
Something like 
$date = $.makeArray($('#divRss li'))
$date.sort(function(a,b) { 
    return new Date(a.date).getTime() - new Date(b.date).getTime() 
});

Where date should be the data('date').
Here is a Fiddle for test/example purpose : https://jsfiddle.net/Baldrani/sj8m8d96/

A: Given the HTML you provide there are no elements with a date attribute. The only date I can see is the value of the .itemDate elements within each li. You can amend your sort() to work with this value instead. Once the sort() has run, you can re-append the li to their parent element in their sorted order. Also note that you don't need to use $.makeArray() on the jQuery object and #divRss does not exist (although I assume this is just missing in your example HTML). 
With all that said, try this:
$('.feedEkList li').sort(function(a, b) {
    var aDate = $(a).find('.itemDate').text();
    var bDate = $(b).find('.itemDate').text();
    return new Date(bDate).getTime() - new Date(aDate).getTime();
}).appendTo('.feedEkList');

Updated fiddle
Note this is ordered in descending date order. To change this to ascending, subtract bDate from aDate.
