Is jQuery difficult to learn?

The answer to this question really depends on your background. If you know JavaScript then it’s not difficult at all, since jQuery it’s just a set of functions.

Usually I hear this question from people who don’t know JavaScript and want to implement jQuery functionality. In that case, learning JavaScript just to use some jQuery is a bit of a task, but you can come functionally literate without too much trouble. For the average user though this will be a bit much, which is why using a CMS like WordPress that can easily integrate jQuery functionality (through plugins and themes) is probably your best bet if you don’t already know JavaScript.