private String getCaptcha()
{
GeetestLib geetest = new GeetestLib(GeetestConfig.publicKey, GeetestConfig.privateKey);
String userID = "test";
Byte gtServerStatus = geetest.preProcess(userID);
Session[GeetestLib.gtServerStatusSessionKey] = gtServerStatus;
Session["userID"] = userID;
return geetest.getResponseStr();
}
