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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 window.open.
  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  

Document Tags and Contributors

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