The HTML5 Spec actually has a nice explanation of how to do the manifest. You can find it here: http://bit.ly/aLbKP0
I wrote a blog post a while back that talks about how browsers handle the manifest files. Forgive the shameless self-promotion, but it might be interesting background reading: http://bit.ly/9WhsO8
Basically, the manifest file is just a special text file that stores a list of the things you want the client to cache. This is the feature of HTML5 that enables offline access to web resources. Think of it as sort of a robots.txt for caching purposes.
I wrote a blog post a while back that talks about how browsers handle the manifest files. Forgive the shameless self-promotion, but it might be interesting background reading: http://bit.ly/9WhsO8
Basically, the manifest file is just a special text file that stores a list of the things you want the client to cache. This is the feature of HTML5 that enables offline access to web resources. Think of it as sort of a robots.txt for caching purposes.