jQuery has taken over in the application-building world, and people have been using it left and right to build new applications, from hobbyist projects to large-scale, enterprise-level applications. There are, however, other toolkits like dojo out there that offer alternatives to jQuery: should you always use jQuery, or is there a reason to switch to one of those other toolkits when the need arises?
First off, it’s always a safe bet to use what you know. If you’re familiar with the jQuery library, it’s almost certain that you’re going to do faster, better work with jQuery than you would with another toolkit. In the time it would take you to learn the ins and outs of a new toolkit you could conceivably have already taken a new application into its alpha stages, depending on the size of the app and how well you know jQuery.
jQuery’s popularity is not to be underestimated, either: it’s got a large and friendly support community online, and it’s more than likely that you’ll find someone able to help you with a thorny jQuery problem in some forums when you can’t figure out the solution from jQuery’s significant documentation. Its popularity also means you’ll be able to find some jQuery developers more easily should management decide that the project in question requires more manpower devoted to it.
The area where many developers worry about jQuery is at the enterprise-level: jQuery is in essence a library, while other frameworks like dojo are full-featured, enterprise toolkits. Many developers are afraid that jQuery can’t handle more significantly complex applications that require things like integration with the Zend framework, for example, or with custom modules or object oriented code. That said, however, jQuery is able to do all of those things: the key difference here is other toolkits simply offer an already integrated solution to the task at hand.
The real truth is that only you and your team can decide what’s best for your application, but in general jQuery is suitable for most applications, enterprise-level or otherwise. The only consideration for a more complex toolkit like dojo comes if you think that your team will spend too much time rolling your own development kit and would benefit from having a development toolchain already in place, then you should choose one of the enterprise-level toolkits afforded to you. Realistically, however, there are going to be few use cases where such a large framework is going to be absolutely necessary for the successful completion of any particular project.
So in the end, the verdict probably leans towards jQuery for most projects, especially if you’re proficient in it: it’s easy to use and develop with, has excellent documentation, and has a large support community due to its popularity. If you need something extremely, significantly complex, however, you need to look at the other toolkits available and decide if it’s a better strategy for your team to either develop the necessary components in-house or use a toolkit that has the components built in!