I\'m starting a web application that will target Mobile Safari on iPhone/iPod Touch. I\'m evaluating the available client-side JavaScript/CSS libraries/frameworks that are
use http://jquerymobile.com/ it is well supported by industry leaders
I second jQTouch being a great full featured solution. But if you are just looking for a JavaScript library I'd recommend XUI. The syntax is based on jQuery but the library is tuned for mobile development.
I like Uranium. It's a lightweight set of widgets. (It also includes the XUI framework). I find jQuery too bloated for mobile use. I need a smaller library. Uranium is a bunch of pre-defined widgets, which I find pretty useful for most functions I want to perform on a mobile site.
My personal preference is jQTouch. It's a great framework to work with and includes both javascript and CSS assets to make web applications that really give the feel of native applications.
For accessing the lower level functionality of the native device, you can always wrap your HTML files, JS + CSS + jQTouch assets into a native app using something like phonegap, rhomobile or appcelerator, however, this does require a mac to compile and deploy the native application to the appstore.
Certainly most of the things I am looking at are just web applications, so jQTouch does the job nicely. Did a blog post combining my thoughts in my detail on my blog, link below:
iPhone and Android Web Application Frameworks
There is also jPint
Old question, but still relevant. Sencha (the new name of the company behind ExtJs) just released the mobile app platform Sencha Tounch for iPhone, iPod, iPad and Android: http://www.sencha.com/products/touch/
Blog post that explains the difference between jQTouch and Sencha Touch: http://9-bits.com/post/723711597/jqtouch-and-sencha-touch
Update: John Resig recently announced that the jQuery team is working on a mobile UI library. Looks promising: http://jquerymobile.com/2010/08/announcing-the-jquery-mobile-project/