This feature is not on a current W3C standards track, but it is supported on the Firefox OS platform. Although implementations may change in the future and it is not supported widely across browsers, it is suitable for use in code dedicated to Firefox OS apps.

This API is available on Firefox OS for privileged or certified applications only.

The zoom() method of the HTMLIFrameElement interface changes the zoom factor of the browser <iframe>'s content. This is particularly useful for zooming in/out on non-touch-enabled devices.


var instanceOfDOMRequest = instanceOfHTMLIframeElement.zoom(zoomFactor);




A unitless number value representing the amount to zoom in or out. It acts like a percentage, so for example 1.1 would zoom in by 10%, whereas 0.9 would zoom out by 10%.


var browser = document.querySelector('iframe');

var zoomFactor = 1;

zoomIn.addEventListener('touchend',function() {
  zoomFactor += 0.1;

zoomOut.addEventListener('touchend',function() {
  zoomFactor -= 0.1;


Not part of any specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support Not supported Not supported Not supported Not supported Not supported
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support Not supported Not supported 1.0.1 Not supported Not supported Not supported

Note: Use of the Browser API requires a privileged app, and browser and/or embed-apps permissions, depending on what you want to do. See Using the Browser API for more details.

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills
 Last updated by: chrisdavidmills,