c# - How to call Confirmation box in IF condition from Code-Behind? -

i'm using linkbutton , dropdown.

when click on linkbutton dropdown appears.

after selecting dropdown value, want confirmation box called javascript appear, ensuring value changed.

i'm calling script in second if condition, it's not working.

after confirmation want change other value , exit condition.

protected void lnkbtnsave_click(object sender, eventargs e) {     if ((ddlhiringmanager.selecteditem != null &&         (ddlhiringmanager.selecteditem.text != lblhiringmanager.text)) &&         (convert.toint32(ddlhiringmanager.selectedvalue)) != -1)     {          if (clientscript.registerstartupscript(typeof(page), "confirm", "<script type='text/javascript'>confirm('are sure want change hiring manager requirement.');</script>"))         {             clsclientmanager objclientmanager = new clsclientmanager();              if (objclientmanager.updatehrmanagerbyreqid(convert.toint32(hdnreqid.value), convert.toint32(ddlhiringmanager.selectedvalue)) > 0)             {                 lblshowhiringmanager.text = ddlhiringmanager.selecteditem.text;             }          }           }     else     {         clientscript.registerstartupscript(typeof(page), "symbolerror", "<script type='text/javascript'>alert('please select hiring manager !');</script>");                 } } 

you cannot use result of registerstartupscript method.

change aspx page code linkbutton given below

<asp:linkbutton id="lnkbtnsave" runat="server" onclick="lnkbtnsave_click"     onclientclick="javascript: return confirm('are sure want change hiring manager requirement.');">save</asp:linkbutton> 

i have added client side click event.

on clicking linkbutton confirmation box. page postback if click ok in confirmation box.