Docs: http://jquerymobile.com/demos/1.0a4.1/#docs/api/methods.html
$.mobile.pageLoading (method)
Show or hide the page loading message, which is configurable via $.mobile.loadingMessage.
Arguments:
Done (boolean, defaults to false, meaning loading has started). True will hide the loading message.
Examples:
//cue the page loader
$.mobile.pageLoading();
//hide the page loader
$.mobile.pageLoading( true );
