Since I have a large monitor I am able to run a very high resolution (1920×1080). As such, I do not have my Firefox window maximized but rather I have it taking the full screen vertically and about half the screen horizontally. There are times I will go to a website, where the developer has decided that the Firefox window should be maximized or a different size. This very annoying as I have to resize the window back the way I want it to be. Even more annoying when I click a link on that site and changes the size of the Firefox window again. Here is an easy way to prevent websites from messing with your Firefox Window:
Firefox 3.6 and 4.0 Windows XP: Tools > Options > Content Tab > click the Advanced button to the right of Enable Java Script (third option down) > In the Advanced JavaScript Settings window, un-check Move or resize existing windows. > Click OK.
Firefox 4.o and newer Windows Vista/7: Firefox Menu > Options > Options > Content Tab > click the Advanced button to the right of Enable Java Script (third option down) > In the Advanced JavaScript Settings window, un-check Move or resize existing windows. > Click OK.
What’s very annoying, is that it’s all or nothing. There’s no way to say that certain (well behaved) websites can do this. Or even better, allow popups to still be resized by Javascript, but not regular windows.
I have this disabled, for the same reason as you, but certain sites open popups with fixed dimensions, and then resize them to fit their content, which it now doesn’t do anymore.
– Michael