如何在jQueryMobile中使用pageLoading来阻止UI

$(document).ready(function () {         
    $('body').append('<div id="block-ui"></div>');      

    $('#ajax_request').click(function(){        
        $('#block-ui').show();
        $.mobile.pageLoading(false);
    });
});

#block-ui {
    display: none;
    cursor: wait;
    position: absolute;
    top: 0px;
    left: 0px;  
    width: 100%;
    height: 100%;
    z-index: 9; 
    background-color: #CCCCCC;
    opacity: 0.5;
}

.ui-header-fixed, .ui-footer-fixed {
    z-index: 8 !important;
}