@viewport

Summary

The @viewport CSS at-rule contains a set of nested descriptors in a CSS block that is delimited by curly braces. These descriptors control viewport settings, primarily on mobile devices.

Syntax

A zoom factor of 1.0 or 100% corresponds to no zooming. Larger values zoom in. Smaller values zoom out.

Descriptors

Browsers are supposed to ignore unrecognized descriptors.

min-width

Used in the determination of the width of the viewport when the document is first displayed.

max-width

Used in the determination of the width of the viewport when the document is first displayed.

width

A shorthand descriptor for setting both min-width and max-width

min-height

Used in the determination of the height of the viewport when the document is first displayed.

max-height

Used in the determination of the height of the viewport when the document is first displayed.

height

A shorthand descriptor for setting both min-height and max-height

zoom

Sets the initial zoom factor.

min-zoom

Sets the minimum zoom factor.

max-zoom

Sets the maximum zoom factor.

user-zoom

Controls whether or not the user should be able to change the zoom factor.

orientation

Controls the document's orientation.

Formal syntax

@viewport {
  <group-rule-body>
}

Examples

@viewport {
  min-width: 640px;
  max-width: 800px;
}
@viewport {
  zoom: 0.75;
  min-zoom: 0.5;
  max-zoom: 0.9;
}
@viewport {
  orientation: landscape;
}

Specifications

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

[1] There is a bug in IE Mobile 10 on older versions of Windows Phone 8, where device-width, when used within @-ms-viewport, evaluates to the screen width in physical pixels rather than normalized CSS pixels, which is wrong according to the specification. However, when used within a viewport <meta> tag, device-width evaluates correctly. According to Microsoft, this bug was fixed in Windows Phone 8 Update 3 (a.k.a. GDR3), although there are some reports that the Lumia Black GDR3 update did not fix the bug (at least on the Lumia 920). For more details and a workaround, see Tim Kadlec's blog post "Windows Phone 8 and Device-Width".

[2]: See bug 747754 – Implement @viewport at-rule

[3]: See WebKit bug 95959

[4]: See Chromium issue #235457: Enable @viewport on all platforms

See also

• <meta>, specifically <meta name="viewport">
• Using the viewport meta tag to control layout on mobile browsers