diff --git a/libraries/ESP8266WebServer/src/ESP8266WebServer.cpp b/libraries/ESP8266WebServer/src/ESP8266WebServer.cpp
index c4db82225..83a68ce9f 100644
--- a/libraries/ESP8266WebServer/src/ESP8266WebServer.cpp
+++ b/libraries/ESP8266WebServer/src/ESP8266WebServer.cpp
@@ -221,6 +221,32 @@ String ESP8266WebServer::arg(const char* name)
 	return String();
 }
 
+String ESP8266WebServer::arg(int i)
+{
+	if (i < _currentArgCount)
+		return _currentArgs[i].value;
+	return String();
+}
+
+String ESP8266WebServer::argName(int i)
+{
+	if (i < _currentArgCount)
+		return _currentArgs[i].key;
+	return String();
+}
+
+int ESP8266WebServer::args(){
+  return _currentArgCount;
+}
+
+bool ESP8266WebServer::hasArg(const char* name)
+{
+	for (int i = 0; i < _currentArgCount; ++i) {
+		if (_currentArgs[i].key == name)
+			return true;
+	}
+	return false;
+}
 
 void ESP8266WebServer::_parseArguments(String data)
 {
@@ -293,6 +319,9 @@ void ESP8266WebServer::_parseArguments(String data)
 
 }
 
+void ESP8266WebServer::onNotFound(TNotFoundHandlerFunction fn){
+  _notFoundHandler = fn;
+}
 
 void ESP8266WebServer::_handleRequest(WiFiClient& client, String uri, HTTPMethod method) {
 	_currentClient   = client;
@@ -312,12 +341,12 @@ void ESP8266WebServer::_handleRequest(WiFiClient& client, String uri, HTTPMethod
 		break;
 	}
 
-	if (!handler)
-	{
+	if (!handler){
 #ifdef DEBUG
 		Serial.println("request handler not found");
 #endif
-		send(404, "text/plain", String("Not found: ") + uri);
+    if(!_notFoundHandler || !_notFoundHandler())
+      send(404, "text/plain", String("Not found: ") + uri);
 	}
 
 	_currentClient   = WiFiClient();
diff --git a/libraries/ESP8266WebServer/src/ESP8266WebServer.h b/libraries/ESP8266WebServer/src/ESP8266WebServer.h
index 6d9c5ffb5..2c3000447 100644
--- a/libraries/ESP8266WebServer/src/ESP8266WebServer.h
+++ b/libraries/ESP8266WebServer/src/ESP8266WebServer.h
@@ -39,22 +39,27 @@ public:
 	void handleClient();
 
 	typedef std::function<void(void)> THandlerFunction;
+	typedef std::function<bool(void)> TNotFoundHandlerFunction;
 	void on(const char* uri, THandlerFunction handler);
 	void on(const char* uri, HTTPMethod method, THandlerFunction fn);
+	void onNotFound(TNotFoundHandlerFunction fn);//called when handler is not assigned
 
 	String uri() { return _currentUri; }
 	HTTPMethod method() { return _currentMethod; }
 	WiFiClient client() { return _currentClient; }
-
+	
+	String arg(const char* name);// get request argument value
+	String arg(int i);// get request argument value buy number
+	String argName(int i);// get request argument name buy number
+  int args();//get arguments count
+  bool hasArg(const char* name);//check if argument exists
+  
 	// send response to the client
 	// code - HTTP response code, can be 200 or 404
 	// content_type - HTTP content type, like "text/plain" or "image/png"
 	// content - actual content body
 	void send(int code, const char* content_type = NULL, String content = String(""));
 
-	// get request argument value
-	String arg(const char* name);
-
 protected:
 	void _handleRequest(WiFiClient& client, String uri, HTTPMethod method);
 	void _parseArguments(String data);
@@ -76,6 +81,7 @@ protected:
 
 	RequestHandler* _firstHandler;
 	RequestHandler* _lastHandler;
+  TNotFoundHandlerFunction _notFoundHandler;
 
 };