jQuery's :first pseudo-selector implementation always returns only a single match. Nokogiri's implementation makes :first a synonym for :nth-child(1), which returns all elements that are the first child of their parents, which is a decidedly different result.
Since :first isn't part of the CSS standard, neither implementation is "wrong" per se, but I believe that most people would expect Nokogiri and jQuery to return the same results.
I would rather have an error message saying that :first is not supported than have it be different from jQuery.
jQuery's :first pseudo-selector implementation always returns only a single match. Nokogiri's implementation makes :first a synonym for :nth-child(1), which returns all elements that are the first child of their parents, which is a decidedly different result.
Since :first isn't part of the CSS standard, neither implementation is "wrong" per se, but I believe that most people would expect Nokogiri and jQuery to return the same results.
I would rather have an error message saying that :first is not supported than have it be different from jQuery.