The read-only Window property innerWidth returns the interior width of the window in pixels. This includes the width of the vertical scroll bar, if one is present.

More precisely, innerWidth returns the width of the window's visual viewport. The interior height of the window—the height of the layout viewport—can be obtained from the innerHeight property.


let intViewportWidth = window.innerWidth;


An integer value indicating the width of the window's layout viewport in pixels. This property is read-only, and has no default value.

To change the window's width, use one of the Window methods for resizing windows, such as resizeBy() or resizeTo().

Usage notes

If you need to obtain the width of the window minus the scrollbar and borders, use the root <html> element's clientWidth property instead.

The innerWidth property is available on any window or object that behaves like a window, such as a frame or tab.


// This will return the width of the viewport
var intFrameWidth = window.innerWidth;

// This will return the width of the frame viewport within a frameset
var intFrameWidth = self.innerWidth;

// This will return the width of the viewport of the closest frameset
var intFramesetWidth = parent.innerWidth;

// This will return the width of the viewport of the outermost frameset
var intOuterFramesetWidth = top.innerWidth;


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

Browser compatibility

BCD tables only load in the browser

See also