Show to wait popup when page loads in the masterpage?

I have link in the master page in sharepoint. when the user clicks on that link It is taking ages to load the page. I want open a popup (jquery will be good) to show and when ever pages popup should disapper.

<asp:ContentPlaceHolder id="PlaceHolderGlobalNavigation" runat="server">
    <map name="Map">
        <area shape="rect" coords="225,16,287,33" href="/_layouts/MyAlerts.aspx" 
        alt=开发者_运维技巧"My Alerts">
    </map>
</asp:ContentPlaceHolder>

How can we handle this?

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As far as i know, u can show the loading image by using CSS. After u complete load, then u swap back to ur desired control. Here is an excellent example. by Dave Ward

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you would have to alter the MyAlerts.aspx page to show the popup/"loading" message and load the portion of the page that was taking a long time through an ajax call. when the success handler is called you can swap out the loading message for the content.