Some terminology that you didn't need to know in 2005: "device pixel": what the screen reports is a pixel. Usually it's a square containing red, green, and blu

Some terminology that you didn't need to know in 2005: "device pixel": what the screen reports is a pixel. Usually it's a square containing red, green, and blue, but not if you use a PenTile display. "CSS pixel" is what widths and clientX are measured in. Interestingly, the CSS spec has always defined a CSS pixel relative to the angle you'd get if you read it, but browsers always treated them as device pixels until they implemented full page zoom. (aka logical pixel in IE8) "screen pixel" (system pixel in IE8) is the unit in which window.screenX is measured. It's what CSS pixel would be at 100% zoom. Mozilla is trying to end the insanity by removing this different measure. http://www.quirksmode.org/blog/archives/2010/04/a_pixel_is_not.html http://www.quirksmode.org/blog/archives/2010/04/a_pixel_is_n...