I want to build a relatively simple version of my site for mobile phones, but I will definitely need JavaScript and jQuery for many functions.
Googling didn't help to find an answer. How is compatibility of jQuery with popular browsers in mobile phones?
I am talking for smartphones. For example, the default browsers for these platforms
and let's add Opera Mobile.
jQuery should work fine on at least the Android and iPhone web browsers (don't know about WinMo), as they fully support JavaScript and are for the most part standards compliant.
If you expand a little bit on which specific features of jQuery you're using, I or others can give a better answer here.
See What's jQuery's mobile support & strategy?. iPhone, Android, and similar WebKit browsers should be compatible. I think you will have many problems with Windows Mobile.
Both Android and iPhone are full featured WebKit browsers (bar plugins). I would be highly surprised if it doesn't work on those.
Should work just fine in current Opera Mobile - if you target older versions (<9.5 AFAIK) you'd need to watch out for this: http://my.opera.com/hallvors/blog/show.dml/1665828
