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Resizes the current window by a certain amount.


window.resizeBy(xDelta, yDelta) 


  • xDelta is the number of pixels to grow the window horizontally.
  • yDelta is the number of pixels to grow the window vertically.


// shrink the window 
window.resizeBy(-200, -200);


This method resizes the window relative to its current size. To resize the window in absolute terms, use window.resizeTo.

Since Firefox 7, it's no longer possible for a web site to change the default size of a window in a browser, according to the following rules:

  1. You can't resize a window or tab that wasn’t created by
  2. You can't resize a window or tab when it’s in a window with more than one tab.


Specification Status Comment
CSS Object Model (CSSOM) View Module
The definition of 'window.resizeBy()' in that specification.
Working Draft

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Contributors to this page: cvrebert, fscholz, teoli, iamanupmenon, ethertank, Sheppy, Mgjbot, Ptak82, Dria, JesseW
Last updated by: cvrebert,
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