StringBuilder sb = new StringBuilder();
             sb.Append('<script language=\'javascript\'> \n');
             sb.Append('function function1()\n');
             sb.Append('{ \n');
             sb.Append('if (document.readyState!=\'complete\') return; \n');
             sb.Append('window.showModalDialog('WebForm1.aspx',window); \n');
             sb.Append('} \n');
             sb.Append('document.onreadystatechange = function1; \n');

             sb.Append('</script>');

             //System.Web.HttpContext.Current.Response.Write();
             Page.RegisterStartupScript('focus', sb.ToString());