Sharepoint2013 Modal Dialog box is not loading

Hi,

I have a simple page uploaded to SharePoint pages library and trying to simulate long running operation with no close wait dialog. Below is the is script what i have.

<script type="text/javascript">        function DoWork()        {            toggleProcessingStatus(true);              //alert("Test");            sleep();            toggleProcessingStatus(false);        }        function sleep() {            for (i = 0; i < 20000000; i++) {    }        }        var waitDialog = null;        function toggleProcessingStatus(showStatus) {                                    if (showStatus) {                LoadSPUIDialogIfNotLoaded();                waitDialog = SP.UI.ModalDialog.showWaitScreenWithNoClose('Updating...', 'Please wait      while update completes...', 150, 330);            }            else {                if (waitDialog != null) {                    waitDialog.close();                }            }        }    </script>

DoWork() method is called from a button click event

<input type="button" id="btnShowDialog" title="Do Long Running Work" name="Do Long Running Work" onclick="javascript: DoWork();" value="Do Long Running Work"/>

If i put a alert() after opening share point modal dialog i see the update modal window.

Any help is greatly appreciated.

Thanks, Mallikarjun

mallikarjun