mDimension Technology have developed a plugin for Safari which lets you not only view Quartz Compositions in a web page, but also interact with them via JavaScript. This is very neat!
So far I’ve been experimenting with creating custom applications (Vidgets) in Xcode which control Quartz Compositions, this plugin appears to give me most of the same functionality within a web page. To control and manipulate the composition, first you must follow the same methods of ‘publishing’ inputs and outputs from a composition as described here.
View source on these pages to see how to send and receive information to and from these inputs via JavaScript. I’m still working it out myself!
Here is a demo page from mDimension with a Quartz Composition embedded.
Here is a quick demo I made up based on the above page. It allows you to load an image by entering its url into a field and clicking outside of the field (don’t need to press enter), and change the spinning text similarly.
Technorati Tags: Quartz Composer, vidget

Hello David.
I see what you are doing with retreiving images. Maybe, you can help. I am getting quite frustrated with a little project. I want to read a series of images in from my website into a qtz composition. The path is http://www.manjitbedi.com/slideshow. When I try to read the folder from within in quartz, I am getting an error. I wonder if it something to do with permissions on with the hosting for my site. Any clues greatly appreciated.
The debug from quartz is slightly odd as well, the path it appears to be searching look manged.
manjitbedi/Library/Screen Savers/http:/www.manjitbedi.com/slideshow” scan started
20:37:22.875 ["[IN} Folder to Scan" @ "Folder SlideShow"] > Could not scan folder at path: /Users/manjitbedi/Library/Screen Savers/http:/www.manjitbedi.com/slideshow
Cheers
Manjit