webBrowser执行js的方法，并返回值，c#后台取值

      private void Form1_Load(object sender, EventArgs e)
        {
            webBrowser1.Navigate(Application.StartupPath + @"i.html");
            txtInfo.Text = webBrowser1.DocumentText;
        }

private void button2_Click(object sender, EventArgs e)
        {

            
            webBrowser1.Document.InvokeScript("GetCode", new object[] { "1567613","228267824","顶一个","D7D796981B62D318"});
            if (webBrowser1.Document.GetElementById("msg") != null)
            {
                HtmlElement element = webBrowser1.Document.GetElementById("msg");
                txtInfo.Text = element.GetAttribute("value");
            }
       

        }

 function GetCode(lBdId, lDocId, text, sessionID) {

     document.getElementById("msg").value = H2(lBdId + '-' + lDocId + '-' + P(text), 16, sessionID);
}

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
    <head>
        <title></title><script  type="text/javascript" src="i.js"></script>
    </head>
    <body>
    <input type=text id=msg />
    </body>
</html>

以html页面作为媒介，将返回的值传递到html中的控件，然后在webBrowser中用

 HtmlElement element = webBrowser1.Document.GetElementById("msg");
                txtInfo.Text = element.GetAttribute("value")
获得值