private bool IsConnectedToInternet()
{
 int Desc;
 return internet.InternetGetConnectedState(out Desc, 0);
} 

private void btnlogin_Click(object sender, EventArgs e)
{
 webBrowser1.Document.GetElementById("id").InnerText =txtuser.Text.ToString().Trim();//fill name
 webBrowser1.Document.GetElementById("passwd").InnerText =txtpwd.Text.ToString().Trim();//fill pwd
 HtmlElement formLogin = webBrowser1.Document.Forms["frmLogin"];
 formLogin.InvokeMember("submit");
 Thread.Sleep(5000);
 herfclick("http://www.yoursiteweb.com/upload.aspx");//这是登录成功的操作,跳转到//upload.asp
 //注意不是直接跳过去的,模拟点击链接
 //SESSION不会丢失
 herfclick("http://www.yoursiteweb.com/copy.aspx"); 
}

private void herfclick(string url)
{
 for (int i = 0; i < webBrowser1.Document.All.Count; i++)
 {
  if (webBrowser1.Document.All[i].TagName == "A" && webBrowser1.Document.All[i].GetAttribute("href").ToString().Trim() ==url)
  {
   webBrowser1.Document.All[i].InvokeMember("click");//引发”CLICK”事件
   break;
  }
 }
 
}

private void callJsMethod(string jsfun,string jsParameter)
//函数名字,函数参数
{
 HtmlDocument doc = webBrowser1.Document;
 doc.InvokeScript(jsfun,new object[]{jsParameter});
}

private void filldate(string txt)
{
 HtmlElement frmWord = webBrowser1.Document.Forms["frmWord"];//找到from
 HtmlElementCollection txtarea = frmWord.GetElementsByTagName("TEXTAREA");
 HtmlElementCollection radio = frmWord.GetElementsByTagName("INPUT");
 radio[2].InvokeMember("click");//选择radio控件
 txtarea[0].InnerText = txt.ToString();
}