@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

Specification	Status	Comment
CSS Device Adaptation The definition of '@viewport' in that specification.	Working Draft	Initial definition

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!

Desktop
Mobile

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari
Basic support	29 (behind a flag) [4]	No support [2]	10 -ms	11.10 Removed in 15 Reintroduced behind a flag in 16	No support [3]

Feature	Android	Chrome for Android	Firefox Mobile (Gecko)	IE Mobile	Opera Mobile	Safari Mobile
Basic support	4.4	29	No support [2]	10-ms[1]	11.10 Removed in 15 Reintroduced behind a flag in 16	No support [3]

[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