Well, that's some comfort at least (the non-live dev environment).
But I just hate the tedium of upload and test, upload and test.
Of course, I do a lot of work in ASP.NET, and MS's Visual Studio gives you a debug environment that is wonderful: You can hardly tell the difference between debugging server-side and client-side code. I can set breakpoints either place and inspect variable values either place and ... (Well, granted, you are stuck using MSIE as a browser during debug, but that just means I need to make a quick run-through with FF and Chrome after things are debugged, to make sure it all works in them as well.)
Even if you crash, you won't take down your main browser, as VS creates a custom development browser for you (still IE, of course).
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.