I need to be able to open a New tab and display a pdf document inside it following a validation on the entered parameters. Here is my code:

<asp:Button ID="GetPaySlipBtn" runat="server" Text="Pay Slip" ForeColor="Navy" OnClientClick="SetTarget();" OnClick="GetPaySlipBtn_Click" />

and a JavaScript inside the page defining the SetTarget()

  function SetTarget() {
           document.forms[0].target = "_blank";
           window.setTimeout("document.forms[0].target='';", 500);
}

And here is the code inside the Onclick Function:

Response.Buffer = true;
                   Response.ContentType = "application/pdf";
                   Response.AddHeader("content-disposition", "inline;filename=" + "Report.pdf");
                   Response.Cache.SetCacheability(HttpCacheability.NoCache);
                   Response.Write( pdfDoc);
                   Response.End();

Now the issue is , when the parameters are not correct and instead of staying on the same page , the page opens another time on a new tab with the error message displayed.

so i have the same page opened twice.

Is there a way to condition the OnClientClick option.

Regards.