Cross Browser Zoom and Pixel Ratio Detector

Forked from https://github.com/yonran/detect-zoom
As of January 2013 @yonran stopped maintaining his source, and is pointing to this repository

Major changes from the original code:

• I removed support for old browsers and cleaned up the original code.
  Supported browsres: IE8+, FF4+, modern Webkit, mobile Webkit, Opera 11.1+
• Added AMD and CommonJS support ("require" and "exports")

Detect-zoom has only two external functions:

• zoom() Returns the zoom level of the user's browser using Javascript.
• device() Returns the device pixel ratio multiplied by the zoom level (Read more about devicePixelRatio at QuirksMode)

This can be used to show higher-resolution canvas or img when necessary.
I'm maitaining it to use Detect-zoom in Wix.com's editor to warn users that their browser is in zoom mode before saving imporant changes to their wabsite.

It is not complete, I need help testing different browsers, patches welcome.

Live Example

http://tombigel.github.com/detect-zoom/

Usage

    <script src="detect-zoom.js"></script>
    <script>
      var zoom = detectZoom.zoom();
      var device = detectZoom.device();

      console.log(zoom, device);
    </script>

AMD Usage

    require(['detect-zoom'], function(detectZoom){
        var zoom = detectZoom.zoom();
    });

License

Detect-zoom is dual-licensed under the WTFPL and MIT license, at the recipient's choice.