Window Sizing
  The buttons and links below can be used to resize your browser window to test a page on different displays. The browser is set to the same size you would get if your display was set to the given screen resolution and you maximized the browser window.

It takes into account the available screen area, which is the screen resolution less the width or height of the task bar and any other screen elements.

It assumes that the window border is four pixels. When the browser window is maximize, this border disappears, so at a screen resolution of 800x600 pixels, the browser size might show as 808x580:

      600  
800     +8  (window border)
+8  (window border)   -28  (taskbar height)
   
 
808     580  

Current dimensions:

These form fields are update on a window resize event to display the current screen and window dimensions.

Screen: x Available: x
Outer Window: x Inner Window: x

Resize window for:

Hit a button to resize the browser window.

Bookmarks:

You can drag the links below to your Bookmarks, Personal Toolbar (Netscape) or Favorites Menu (IE) for quick access.

Source

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