I thought Squidfingers was cool, but Jesse Ruderman’s bookmarklets are about a zillion times cooler, only in a really geeky way. Want to see, in the status bar, the document-tree path of whatever element your mouse pointer is over? Jesse’s got your back. Look up the WHOIS record for whatever site you’re visiting? Check. View style sheets, see the generated source, show the values for named anchors, kill off CSS temporarily, go up a directory level, view whatever cookies relate to the site you’re visiting, sort tables, view HTTP headers, zoom images, or even resize fixed-pixel layouts? Oh yeah. And that’s only a fraction of what Jesse has on tap. My only real problem is that there’s nowhere near enough room on my personal toolbar to hold all the bookmarklets I want to install. Even with dropdown folders it’s going to be a tight fit.
That reminds me of another cool bookmarklet I saw a while back but never pointed out: Simon Willison’s Image Drag. Visit a page, click the bookmarklet, and drag images around to see if you like them better in other spots. Wow. Talk about making design-change previews easier!
Those bookmarklets, plus the features that Henrik Gemal just recently wrote about, makes Mozilla a nearly ideal Web development environment all on its own. Invest a little time in setting things up to your liking, and the Web is your oyster. Amazing stuff.