I want to share with you some important codes that you may need during JQuery Mobile development.These codes are tested on Alpha 4 version.

Beta 1 has been released before two days, Therefore I will test them in my current project and let you know if there is any changes :

Show and hide back button in your Application

 $(document).bind("mobileinit", function () {

           $.mobile.page.prototype.options.addBackBtn = true;

       });

Customizing the back button text

$(document).bind("mobileinit", function () {

$.mobile.page.prototype.options.backBtnText = "previous";

});

Hide "Close button" for dialog programatically:

  $('[data-role=dialog]div[id="YourDiaogdivID"]').live('pagecreate', function (event) {

     $("a[data-icon='delete']").hide();

        });

Change Select option element index:

     var myselect = $("select#foo");

       myselect[0].selectedIndex = 0; //The new index

       myselect.selectmenu("refresh"); //uset this line of code after any updating on the select element 

Change Select optoin elemetn text value:

   $("select#foo").parent().contents().children('.ui-btn-text').text('Your Text Here');

Refreshing a checkbox

   $("select#foo").parent().contents().children('.ui-btn-text').text('Your Text Here');

Hide select option element

 $('#foo').parent().hide();

Hide and Show Page Loading Message :

 $.mobile.pageLoading(); //Show

 $.mobile.pageLoading(true); //hide

overriding $.mobile.loadingMessage

$(document).bind("mobileinit", function () {

    $.mobile.loadingMessage = 'My Loading Message';

});

Hide and Show jQuery-Mobile-Themed-DatePicker 

  $(".ui-datepicker").hide();

  $(".ui-datepicker").show();

Build your Custom Loading Message :

          $('#CustomeLoadingMessage').hide();//Hide the div 

            $('# CustomeLoadingMessage').ajaxStart(function () {

                $(this).show();

            });

            $('# CustomeLoadingMessage').ajaxStop(function () {

                $(this).hide();

            });

I wil publish other important codes soon.

Hope that helps.