Making some part of data offline and how tho synchronize the with server

[serdemwigi]

my application gets many data from server such as:

categories, available cities, available zip codes ( which are very rarely changed!)
doctor information (which depends on user geo location and changes often)

To make the application performance better I want to save the rarely changed data offline in localstorage. On the other hand I must detect in any way that my localstorage is not uptodate and if this is the case I must update them.

Question is: How can I detect that localstorage data is not uptodate and there is a need to synchronize them again with server.

This is a standart problem for applications with server - client communication so I hope there exist a standard solution pattern for it.

Thanks a lot for any hint.

[mitchellsimoens]

I have timestamps of last data update and save it along with the localstorage data. I would then do an Ajax call to see if a newer timestamp is available, if it is then I get data and save it to localstorage store and update.

[serdemwigi]

Do you have a code fragment for this?