how can i run ~~~.aspx page without popup in c#?

below code for calling some page and i don't want to popup.
Below code is calling default2.aspx but do not execute javascript which is in the default2.aspx.
url = "http://localhost:56286/PIS_INTERFACE/default2.aspx";
URLReq = (HttpWebRequest)WebRequest.Create(url);
URLRes = (HttpWebResponse)URLReq.GetResponse();

Below code is default2.aspx.

<script type="text/javascript">
alert("default2.aspx");
</script>
</body>
...