Let's say you want to quickly try out some small stylesheet changes, but you don't want to (or prefer not to, or for some reason temporarily you just can't) modify your application's CSS file(s). In FF it's easy - you have Firebug and you can play with styles until blue in the face. And in case you do get blue in the face and start making so many changes that you get lost, you can create a new clean and tidy CSS file, place it on your hard drive and use Web Developer extension to load it (Menu CSS->Add User Style Sheet). With WebDev Extension you can also Edit CSS right there, although unfortunatelly it's not always working when you have frames.
OK, there are options for Firefox. But how about IE?
In IE you have IE Developer Toolbar, definitelly helpful, but you can only modify element styles, not the stylesheet rules. So? A tiny little bookmarklet to the rescue!
My bookmarklet assumes you have a file called
C:\user.css and loads this stylesheet on demand in your page, in every frame, just in case you use frames. Simple, yet useful, I hope. Here's the (readable) code:
To install and play around
Right-click this link and add it to your favourites:
Have in mind that this is IE-only (tested IE7). I don't think FF will allow you to access files on your local drive like this. But for FF you have the tools to do this anyway.
Another option to load local stylesheets in IE is to use the user CSS capability built in the browser, you can find it under Tools/Internet Options/Accessibility, but this will load your user CSS first (as opposed to last as the case is with my bookmarklet), so the "real" style definitions will overwrite yours, unless you always use
!important and the "real" styles don't.
Have fun with the custom CSS and let me know how you find it.