I'm surprised no one has already mentioned it:
- A lot of web developers default to using JQuery without considering the alternatives
- And end up including it on a web page to do a few trivial tasks which could easily be done in pure JavaScript
- The result is that users have to wait for the whole library to download and it slows down web browsing
Also:
- Some web developers get carried away with the design of web pages, and end up developing unnecessarily complex web pages because of the power of JQuery
- Just because JQuery enables you to create scripts with good cross-browser compatibility it doesn't mean that the end result is usable on different devices / interfaces
- I'd also argue the cross-browser compatibilty because I've seen instances of webkit not playing well with JQuery
- JQuery encourages "fast" scripting - but if you rush it you are likely to have missed something out
- Writing in JavaScript from scratch is slower - but I believe that you end up with a more complete solution which more closely matches the users needs
- Using JQuery can shift the focus of the web developer to creating web sites which are highly graphical and visually appealing, whereas the focus should be on functionality and usability
- JQuery is not a silver bullet for web development
I am biased here because I don't use JQuery, but it is because I haven't found a need for it yet - maybe it's because I focus more on usability and functionality rather than making the user interface look pretty (sorry I know JQuery can do more than that).
