Does .css() automatically add vendor prefixes?

As @zeroflagL wrote it appears that since jQuery 1.8.0 .css() does add browser specific prefixes (see this).

In earlier versions this is not done automatically by jQuery’s .css(). You will have to do it by yourself or you can use jQuery’s .cssHooks() to add vendor prefixes.

Code example from here:

(function($) {
  if ( !$.cssHooks ) {
    throw("jQuery 1.4.3+ is needed for this plugin to work");
    return;
  }

  function styleSupport( prop ) {
    var vendorProp, supportedProp,
        capProp = prop.charAt(0).toUpperCase() + prop.slice(1),
        prefixes = [ "Moz", "Webkit", "O", "ms" ],
        div = document.createElement( "div" );

    if ( prop in div.style ) {
      supportedProp = prop;
    } else {
      for ( var i = 0; i < prefixes.length; i++ ) {
        vendorProp = prefixes[i] + capProp;
        if ( vendorProp in div.style ) {
          supportedProp = vendorProp;
          break;
        }
      }
    }

    div = null;
    $.support[ prop ] = supportedProp
    return supportedProp;
  }

  // check for style support of your property 
  // TODO by user: swap out myCssPropName for css property
  var myCssPropName = styleSupport("myCssPropName");

  // set cssHooks only for browsers that
  // support a vendor-prefixed border radius
  if (myCssPropName && myCssPropName !== 'myCssPropName') {
    $.cssHooks["myCssPropName"] = {
      get: function(elem, computed, extra) {
        // handle getting the CSS property
        return $.css(elem, myCssPropName);
      },
      set: function(elem, value) {
        // handle setting the CSS value
        elem.style[myCssPropName] = value;
      }
    };
  }
})(jQuery);