jQuery and its cousins are great, and by all means use them if it makes it easier to develop your application. If you’re developing a library on the other hand, please take a moment to consider if you actually need jQuery as a dependency.
Some developers believe that jQuery is protecting us from a great demon of browser incompatibility when, in truth, post-IE8, browsers are pretty easy to deal with on their own. Go and check out this tool: You Might Not Need jQuery.
