How to add autosave support to 3rd party fieldtype in EE that uses a custom table.

autosave.js

// Add Autosave support
if(typeof EE.publish == "object" && EE.publish.autosave == "object" && EE.publish.autosave.interval > 10)
{
    // 3 seconds before the defined interval
    interval = (EE.publish.autosave.interval - 3) * 1000;

    setInterval({
        run: function() {
            // Do whatever you need to do here, probably an ajax request, to save data to custom table.
        }
    }.run, interval);
}