AJAX 中，让 UpdateProgress 中的内容显示在页面正中央

< asp:UpdateProgress ID = " UpdateProgress1 "  runat = " server "  AssociatedUpdatePanelID = " UpdatePanel1 " >
         < ProgressTemplate >
           
             < div style = " position:absolute;left:50%;top:50%; " >
                < table width = " 214 "  align = " center " >
                < tr >
                < td > 正在加载数据,请稍候 </ td >
                 < td >< img src = " images/loading_16x16.gif "  alt = " 请稍候 " /></ td >
                </ tr >
                < tr >
                < td colspan = " 2 " >< img src = " images/pleasewait.gif "   /></ td >      
                </ tr >
                </ table >
             </ div >
            

         </ ProgressTemplate >
     </ asp:UpdateProgress >

关键是这句话：

<div style="position:absolute;left:50%;top:50%;">