Crosspixel - like PixelPerfect for Firefox, only in any browser

Crosspixel is a small Javascript program (about 15 Kb), which shows the layout on top of the layout; like PixelPerfect for Firefox, only works in any browser :)
It works like this:

1. download crosspixel.js and connect to your html file;
2. specify the path to your layout file and its size;
3. a panel will appear in the browser that allows you to show / hide the layout (changes the size of the browser window under the layout when it is displayed, restores the previous size when hidden), change its transparency.

GitHub project