Wait a minute!
There is already such a button!
1/ Go to the page where you already inserted data in fields.
2/ Instead of clicking on “Add Row” just hover over the right corner of the first field and click on the + sign which should appear.
A new row of the repeater field will be created above all the other already created.
This would be a great feature! When I add a new news (or article or image), I want it on the top of the page, not the bottom.
In the mean time I looked around for a JQuery solution but did not find one.
The following one just reverse the number of the <ol>
but not its content:
http://www.impressivewebs.com/reverse-ordered-lists-html5/