Some of you probably saw my InjectCSS bookmarklet in my bookmarklets journal
. This is a modification of it, to inject the style tags with numbered IDs. The style injector page above is the modified bookmarklet and a demo of how it works. Feel free to inject some CSS (or some random key bashing, won't matter) to check it out.
There is now a second bookmarklet, GetCSS, which will present all the injected CSS for you in a "popup" div.
If you're wondering why I added IDs to the style tags, it's so that the second bookmarklet to pull the CSS out knows what to look for, and by design ignores the built-in style tags on the page you're working with.
Why is this thing useful? If you're designing or modifying a skin on some site, it's easier to do it live than to hit reload every few seconds. You can get a bookmarklet to nuke all the CSS on a page from Squarefree, and from there this InjectCSS+ bookmarklet is a damn handy tool because the CSS you inject to test can be pulled back out for you (provided you don't hit reload or something) as soon as you get it looking right. No wondering, "Did I give it 2px padding or 3px?" because it's right there exactly as you entered it.
There's also a thread at TEM.