Redmonk analyst Stephen O'Grady and I have been batting the challenges of persistence in Web browsers back and forth over the last week. Obviously exasperated with something, he tweeted (via Twitter) how he'd like to see a browser have the ability to recall recently visited Web pages from a local cache of some sort. I immediately replied, thinking what he was really looking for was off-line persistence of a Web application and, after Twitter failed us in the ability to carry the dialog, we took to the blogs (him, me) to continue the conversation.Offline persistence of anything in the browser -- pages, appications, data, etc. -- is an incredibly tricky problem. So much so that we'll be having an open conversation about it at Mashup Camp in less than two weeks (there's still room to join us).

O'Grady makes it clear that he's not looking for the whole enchilada -- the ability to interact with Web pages while offline as though he were online. He's after something that's not quite so ambitious -- just get him the old page(s) back (with whatever data he may have last filled into it) regardless of the browser's state of connectivity. Presumably, that information is either in the browser's cache already or something can be done to make sure it's there and easily retrieved. I agree. If this is easily done, then someone please do it. It would go a long ways towards improving the overall Web experience for a lot of us.

But is it easily done? Or, better put, is it trivial enough to warrant the effort or is so non-trivial that shooting for the moon -- offering the same capability as a part of a Google Gears-style off-line persistence of Web apps -- makes more sense. O'Grady blogged my question and his response:

I'm not so sure and responded as such directly on his blog with the following comment:

To be honest, I'm pretty sure most of what I'm saying is technically accurate (I mistakenly left out my concerns about security with such an architecture). But, on the same token, things under the hoods of browsers may have progressed to a point where I need to be taken out to the woodshed for a technical spanking. I've only managed to keep half an eye on the situation over the last year and know things have improved dramatically.

Or perhaps the answer is a bit simpler. For example, why, when I hit my browser's back button, am I sometimes returned to a Web form that still has all my user-entered data in it while at other times, hitting the back button takes me to a completely blank form (as though I never entered anything). I most often notice this in e-commerce situations. Then again, when the browser's back button is involved, the implication is that the original form was submitted (thereby updating the page's state).

If you have thoughts on this, please do share them with us.