jQuery Media Helper Utilities from jQuery Mobile:

resolution and CSS media query related helpers and behavior

Dual licensed under the MIT (MIT-LICENSE.txt) and GPL (GPL-LICENSE.txt) licenses.

Demo page:

http://filamentgroup.com/examples/jquery-media-helpers/sample.html

Exposed utilities:

• orientationchange event from jQuery Mobile

  Handler automatically falls back to resize event in browsers that don't natively support it

  The event object contains an "orientation" property, which will equal either "portrait" or "landscape"

  Examples:

  $(window).bind('orientationchange', function(event){
      //alert( event.orientation );
  });

• $.mh.media method: pass a CSS media type or query and get a bool return

  Note: this feature relies on actual media query support for media queries, though types will work most anywhere

  Examples:

  $.mh.media('screen') //>> tests for screen media type
  $.mh.media('screen and (min-width: 480px)') //>> tests for screen media type with window width > 480px
  $.mh.media('@media screen and (-webkit-min-device-pixel-ratio: 2)') //>> tests for webkit 2x pixel ratio (iPhone 4)

• Cross-browser media-query width and orientation breakpoint classes

  This script automatically adds classes to the HTML element:

  - "portrait" or "landscape" for orientation
  
  - Min/Max width breakpoint classes for the following widths (by default):
  
      320px, 480px, 768px, 1024px
  
      ...which translate to classes that correspond to media query sytnax:
  
      .min-width-480px, .max-width-1024px, etc

  You can add breakpoints by number or array, like so:

  $.mh.addResolutionBreakpoints( 500 );
  $.mh.addResolutionBreakpoints( [500, 1200] );