Sisyphus. js is a jQuery plugin for Gmail-like client-side drafts saves with some more features. Imagine you're filling a complex form on site, or typing effervescent and extensive comment. And when you're almost done with that browser is crashed, or you closed tab mistakenly, or electricity is turned off, or something else break your efforts. Disgusting, huh?
With Sisyphus on site you just reopen page in your modern (with HTML5 support) browser and see all your changes at that forms. It's lightweight (3.5 KB) jQuery plugin uses Local Storage to prevent your work being lost.