What are jQuery CSS functions?
Well these are function which help you modify different CSS properties with JavaScript. You know you can do that in “pure” evangelistic JS, but normally every library comes with its own bunch of functions that do the job. In fact in jQuery the things are little bit more complicated because the returned value of those CSS modifiers is yet again a object of the element you modify, which is the same object as this you’ve selected with one of the selectors in jQuery.
This is extremely useful when it comes to chains and you chain several functions using the dot operator. Thus you call more and more functions for every selector and perform a modifier every time you call them.