Update: Please note that this information is obsolete and does not work with the new completely-rewritten jData host library.

When not using the postMessage API but using the HTTP query parameters API, you used to have to use the “callback” parameter and do something like callback=location.href="http://example.com/%3Fvalue="+encodeURIComponent(jdata)+"%26item="+locacation.search.replace… (and some code to figure out what item is being used) to be able to add support for browsers that support localStorage but not postMessage via server-side. I have simplified this by adding an “r” parameter. The r parameter is a URI that the jData frame will redirect to and you can include two different variables in the URI.

The first parameter is %i, which is automatically replaced with the item being accessed. The second parameter is %v, which is the value of the item being accessed.

Example: http://jdata.eligrey.com/?get=personal.fullname&r=http://example.com/?item=%i&value=%v

This redirects to http://example.com/?item=personal.fullname&value=Elijah%20Grey for me. If an item is not set, %v will either be null (Firefox & Safari nightlies) or undefined (IE) depending on the browser, but as not to confuse with a string of “null” or “undefined”, I have it return an empty string when it is undefined or null.