Got my iPad yesterday and starting playing with the project I’m working on and mobile safari. Disappointingly LocalStorage in mobile safari on the iPad appears to behave differentially than the desktop version of webkit. I started getting errors, keys not being found and quota exceptions at quite low volumes of data.
The developer tools are good though (Settings > Safari > Developer) however unlike the desktop version don’t allow you to see localStorage databases which makes resetting, editing and debugging harder.
Following mozilla’s response to webdatabases with their (in my view a better approach) indexedDB it will be interesting to see what finally is adopted by WHAT-WG and the W3C and then makes it’s way back into webkit. Sadly this seems medium term future and with iPhone OS 4 shipping soonish it will mean 2 competing implementations with slightly different semantics for a while.