Android Question From webview to ph browser

Hi,

I am using webview_pageFinished to load a web page with username and password using

Javascript.Append("document.frmLogin.username.value='"&pwuser&"';")
Javascript.Append("document.frmLogin.password.value='"&pwpin&"';")
WebViewExtras1.ExecuteJavascript(Javascript.ToString)

So far the webview page loaded nicely with the username and password. How do I switch to phone browser after or before "login" in order to handle the "popup" event in the website?

Thanks