We are starting up a new project, with Springs inbuilt support for DOJO , we thought we will give it a try ,but later found that customizing the DOJO widgets were not an easy task,(Our custom CSS were being ignored, dont know whether we are doing something wrong here) .
The alternative would be Jquery, we dont have much experience in that as well, hence if you can give some directions based on your experiences that will be great
I'd give the upper hand to jQuery these days. It's not only easy to extend (the very subject of this week's promotion), its user community is thriving. This means that's it's easier to get help with, to find answers to questions, and even to find plugins that do just about anything.
I echo Bear's comments. When I was using Dojo a few years back, the documentation was lax and IBM's extensions made things difficult to understand. It might be better outside an IBM implementation, but using jQuery has been an improvement both from implementation and support available.
I haven't used Dojo but have found jQuery very easy to use. The writers of jQuery recognised that jQuery couldn't and shouldn't do everything and so included numerous extension points so that additional functionality could be integrated into the normal jQuery processing. You can see the result of this in the large third-party plugin community, so many requirements are already available as plugins.