Pixel Perfect: Overlay HTML On Websites For Better Testing
Pixel Perfect is a Firebug plugin which enables you to overlay a web composition on any developed HTML.
By switching between on & off, you can see easily howmany pixels you’re off with the development.
You can play with the opacity of the overlay to better see or totally disable the design below.
Move controls enables you to fine tune the position of the overlay. To give an example, you can exactly position a new menu over an old one to see if it fits or not.