How to get alert message before redirect a page

You need to write: ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", " alert('User details saved sucessfully'); window.open('frmDisplayUsers.aspx');", true); Please note that I have removed the script tags as the last parameter true means you must not use the script tag. This code worked for me. If you have any problem let me know. In addition you can use setTimeout to delay the window open that might not be a very bad choice.

The best way, if possible, is to put the code into the OnClientClick. <asp:Button OnClientClick=" alert('blah?');" runat="server" /> The problem with putting it into a startupscript is that the startupscript is run on postback, not real time. The redirect will happen before the postback. (possibly) The other solution of course is to put the redirect into the startupscript code. The page will post back, the script will run and then it will redirect.