iUI is one of the oldest and most famous libraries for making iPhone Web applications.

It has the following limitations, however:

• transitions do not feel smooth because it does not use CSS3 animations
• it has a very strict idea about the structure of your HTML - this makes many page layouts impossible without hacking iUI's code

A thread from March 2009 discussing iUI. 

Some libraries "inspired by" iUI include Magic Framework and ciUI .