jquery mobile: Object [object Object] has no method 'jqmData'-Collection of common programming errors

I am relatively new to Jquery and Jquery mobile, I was just trying and tutorial to add Loading animation on the page, I was simply following the code provided in one of the demos. However I am getting the following error.

Uncaught TypeError: Object [object Object] has no method 'jqmData' 

I am using the following code snippet and javascript

Refresh


window.$ = window.jQuery = WLJQ;
$( document ).on( "click", ".show-page-loading-msg", function() {
var $this = $( this ),
    theme = $this.jqmData( "theme" ) || $.mobile.loader.prototype.options.theme,
    msgText = $this.jqmData( "msgtext" ) || $.mobile.loader.prototype.options.text,
    textVisible = $this.jqmData( "textvisible" ) || $.mobile.loader.prototype.options.textVisible,
    textonly = !!$this.jqmData( "textonly" );
    html = $this.jqmData( "html" ) || "";
$.mobile.loading( "show", {
        text: msgText,
        textVisible: textVisible,
        theme: theme,
        textonly: textonly,
        html: html
});

setTimeout(WL.Client.reloadApp, 5000);
$.mobile.loading( "hide" );
});

The error is pointing to this line in the javascript theme = $this.jqmData( "theme" )
when i debugged on browser console i was able to see the button data values assigned to the $this variable Please advice,