javascript - Show div from ASP.NET code -

i have div hidden originally:

<div id="loading" class="window">     <img src="../images/test.gif" /> </div> 

how can call div shown while thread running

thread thread = new thread(test); thread.start()  private void test() { //code see div } 

edit: want div appear on top of page user wont able click on else

update

remove display:none class , replace div asp.net control:

<asp:panel id="loading" cssclass="window" runat="server" visible="false">     <img src="../images/test.gif" /> </asp:panel> 

then:

private void test() {     loading.visible = true; }