How to open popup in c# code behind?

   ClientScript.RegisterStartupScript(this.GetType(), "newWindow", "<script>window.open('p.aspx', '', 'top=100,left=300,menubar=no,toolbar=no,location=no,resizable=no,height=750,width=850,status=no,scrollbars=no,maximize=null,resizable=0,titlebar=no');</script>");