I have a JS script which I wrote in my code behind. This is not giving me any err or anything but it is not showing me an alert mesg. I am using Visual Studio 2010 with 4.0 framework. Here is my code:

MessageBox1("Testing my Message"); //Calling Function!

 private void MessageBox1(string msg) //This is in the code behind of the page.

        // Cleans the message to allow single quotation marks
        string cleanMessage = msg.Replace("'", "\\'");
        string script = "<script type=\"text/javascript\">alert('" + cleanMessage + "');</script>";

        // Gets the executing web page
        Page page = HttpContext.Current.CurrentHandler as Page;

        // Checks if the handler is a Page and that the script isn't allready on the Page
        if (page != null && !page.ClientScript.IsClientScriptBlockRegistered("alert"))
            page.ClientScript.RegisterClientScriptBlock(typeof(CommSetup), "alert", script);

Why it is not showing any alert box?