diff --git a/web-server/web-server.c b/web-server/web-server.c
index c1bfb6f..4689014 100644
--- a/web-server/web-server.c
+++ b/web-server/web-server.c
@@ -8,14 +8,31 @@
 #include "cmd.h"
 #include "serbridge.h"
 
+// the file is responsible for handling user defined web-pages
+// - collects HTML files from user image, shows them on the left frame
+// - handles JSON data coming from the browser
+// - handles SLIP messages coming from MCU
+
 #define WEB_CB "webCb"
+#define MAX_ARGUMENT_BUFFER_SIZE 1024
 
-#define MAX_VARS 20
+struct ArgumentBuffer
+{
+	char argBuffer[MAX_ARGUMENT_BUFFER_SIZE];
+	int  argBufferPtr;
+	int  numberOfArgs;
+};
 
 static char* web_server_reasons[] = {
-  "load", "refresh", "button", "submit"
+  "load",     // readable name for RequestReason::LOAD
+  "refresh",  // readable name for RequestReason::REFRESH
+  "button",   // readable name for RequestReason::BUTTON
+  "submit"    // readable name for RequestReason::SUBMIT
 };
 
+// this variable contains the names of the user defined pages
+// this information appears at the left frame below of the built in URL-s
+// format:    ,"UserPage1", "/UserPage1.html", "UserPage2", "/UserPage2.html", 
 char * webServerPages = NULL;
 
 char * ICACHE_FLASH_ATTR WEB_UserPages()
@@ -23,6 +40,7 @@ char * ICACHE_FLASH_ATTR WEB_UserPages()
 	return webServerPages;
 }
 
+// generates the content of webServerPages variable (called at booting/web page uploading)
 void ICACHE_FLASH_ATTR WEB_BrowseFiles()
 {
 	char buffer[1024];
@@ -34,37 +52,35 @@ void ICACHE_FLASH_ATTR WEB_BrowseFiles()
 		espFsIteratorInit(userPageCtx, &it);
 		while( espFsIteratorNext(&it) )
 		{
-			int nlen = os_strlen(it.name);
-			if( nlen >= 6 )
+			int nameLen = os_strlen(it.name);
+			if( nameLen >= 6 )
 			{
-				if( os_strcmp( it.name + nlen-5, ".html" ) == 0 )
+				// fetch HTML files
+				if( os_strcmp( it.name + nameLen-5, ".html" ) == 0 )
 				{
-					char sh_name[17];
+					int slashPos = nameLen - 5;
 					
-					int spos = nlen-5;
-					
-					while( spos > 0 )
-					{
-						if( it.name[spos+1] == '/' )
-							break;
-						spos--;
-					}
+					// chop path and .html from the name
+					while( slashPos > 0 && it.name[slashPos-1] != '/' )
+						slashPos--;
 					
-					int ps = nlen-5-spos;
-					if( ps > 16 )
-						ps = 16;
-					os_memcpy(sh_name, it.name + spos, ps);
-					sh_name[ps] = 0;
+					// here we check buffer overrun
+					int maxLen = 10 + os_strlen( it.name ) + (nameLen - slashPos -5);
+					if( maxLen >= sizeof(buffer) )
+						break;
 					
 					os_strcat(buffer, ", \"");
-					os_strcat(buffer, sh_name);
+					
+					int writePos = os_strlen(buffer);
+					for( int i=slashPos; i < nameLen-5; i++ )
+					  buffer[writePos++] = it.name[i];
+					buffer[writePos] = 0; // terminating zero
+					
 					os_strcat(buffer, "\", \"/");
 					os_strcat(buffer, it.name);
 					os_strcat(buffer, "\"");
 				}
 			}
-			if( os_strlen(buffer) > 600 )
-				break;
 		}
 	}
 	
@@ -76,6 +92,7 @@ void ICACHE_FLASH_ATTR WEB_BrowseFiles()
 	os_memcpy( webServerPages, buffer, len );
 }
 
+// initializer
 void ICACHE_FLASH_ATTR WEB_Init()
 {
 	espFsInit(userPageCtx, (void *)getUserPageSectionStart(), ESPFS_FLASH);
@@ -83,288 +100,339 @@ void ICACHE_FLASH_ATTR WEB_Init()
 		os_printf("Valid user file system found!\n");
 	else
 		os_printf("No user file system found!\n");
-	WEB_BrowseFiles();
+	WEB_BrowseFiles(); // collect user defined HTML files
 }
 
-int ICACHE_FLASH_ATTR WEB_CgiJsonHook(HttpdConnData *connData)
+// initializes the argument buffer
+static void WEB_argInit(struct ArgumentBuffer * argBuffer)
 {
-	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
+	argBuffer->numberOfArgs = 0;
+	argBuffer->argBufferPtr = 0;
+}
+
+// adds an argument to the argument buffer (returns 0 if successful)
+static int  WEB_addArg(struct ArgumentBuffer * argBuffer, char * arg, int argLen )
+{
+	if( argBuffer->argBufferPtr + argLen + sizeof(int) >= MAX_ARGUMENT_BUFFER_SIZE )
+		return -1; // buffer overflow
 	
-	void * cgiData = connData->cgiData;
+	os_memcpy(argBuffer->argBuffer + argBuffer->argBufferPtr, &argLen, sizeof(int));
 	
-	if( cgiData == NULL )
+	if( argLen != 0 )
 	{
-		if( !flashConfig.slip_enable )
-		{
-			errorResponse(connData, 400, "Slip processing is disabled!");
-			return HTTPD_CGI_DONE;
-		}
-		CmdCallback* cb = cmdGetCbByName( WEB_CB );
-		if( cb == NULL )
-		{
-			errorResponse(connData, 500, "No MCU callback is registered!");
-			return HTTPD_CGI_DONE;
-		}
-		if( serbridgeInProgramming() )
-		{
-			errorResponse(connData, 500, "Slip disabled at programming mode!");
-			return HTTPD_CGI_DONE;
-		}
-		
-		char reasonBuf[16];
-		int i;
-		int len = httpdFindArg(connData->getArgs, "reason", reasonBuf, sizeof(reasonBuf));
-		if( len < 0 )
-		{
-			errorResponse(connData, 400, "No reason specified!");
-			return HTTPD_CGI_DONE;
-		}
-		
-		RequestReason reason = INVALID;
-		for(i=0; i < sizeof(web_server_reasons)/sizeof(char *); i++)
-		{
-			if( os_strcmp( web_server_reasons[i], reasonBuf ) == 0 )
-				reason = (RequestReason)i;
-		}
+		os_memcpy( argBuffer->argBuffer + argBuffer->argBufferPtr + sizeof(int), arg, argLen );
+		argBuffer->numberOfArgs++;
+	}
+	
+	argBuffer->argBufferPtr += argLen + sizeof(int);
+	return 0;
+}
+
+// creates and sends a SLIP message from the argument buffer
+static void WEB_sendArgBuffer(struct ArgumentBuffer * argBuffer, HttpdConnData *connData, int id, RequestReason reason)
+{
+	cmdResponseStart(CMD_WEB_REQ_CB, id, 4 + argBuffer->numberOfArgs);
+	uint16_t r = (uint16_t)reason;
+	cmdResponseBody(&r, sizeof(uint16_t));                                      // 1st argument: reason
+	cmdResponseBody(&connData->conn->proto.tcp->remote_ip, 4);                  // 2nd argument: IP
+	cmdResponseBody(&connData->conn->proto.tcp->remote_port, sizeof(uint16_t)); // 3rd argument: port
+	cmdResponseBody(connData->url, os_strlen(connData->url));                   // 4th argument: URL
+	
+	int p = 0;
+	for( int j=0; j < argBuffer->numberOfArgs; j++ )
+	{
+		int argLen;
+		os_memcpy( &argLen, argBuffer->argBuffer + p, sizeof(int) );
 		
-		if( reason == INVALID )
-		{
-			errorResponse(connData, 400, "Invalid reason!");
+		char * arg = argBuffer->argBuffer + p + sizeof(int);
+		cmdResponseBody(arg, argLen);
+		p += argLen + sizeof(int);
+	}
+	
+	cmdResponseEnd();
+}
+
+// this method processes SLIP data from MCU and converts to JSON
+// this method receives JSON from the browser, sends SLIP data to MCU
+static int ICACHE_FLASH_ATTR WEB_handleJSONRequest(HttpdConnData *connData)
+{
+	if( !flashConfig.slip_enable )
+	{
+		errorResponse(connData, 400, "Slip processing is disabled!");
+		return HTTPD_CGI_DONE;
+	}
+	CmdCallback* cb = cmdGetCbByName( WEB_CB );
+	if( cb == NULL )
+	{
+		errorResponse(connData, 500, "No MCU callback is registered!");
+		return HTTPD_CGI_DONE;
+	}
+	if( serbridgeInProgramming() )
+	{
+		errorResponse(connData, 500, "Slip disabled at uploading program onto the MCU!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	char reasonBuf[16];
+	int i;
+	int len = httpdFindArg(connData->getArgs, "reason", reasonBuf, sizeof(reasonBuf));
+	if( len < 0 )
+	{
+		errorResponse(connData, 400, "No reason specified!");
 			return HTTPD_CGI_DONE;
-		}
-		
-		char  body[1024];
-		int   bodyPtr = 0;
-		int   argNum = 0;
-		char *argPos[MAX_VARS];
-		int   argLen[MAX_VARS];
-		
-		switch(reason)
-		{
-			case BUTTON:
-				argLen[0] = httpdFindArg(connData->getArgs, "id", body, sizeof(body));
-				if( argLen[0] <= 0 )
+	}
+	
+	RequestReason reason = INVALID;
+	for(i=0; i < sizeof(web_server_reasons)/sizeof(char *); i++)
+	{
+		if( os_strcmp( web_server_reasons[i], reasonBuf ) == 0 )
+			reason = (RequestReason)i;
+	}
+	
+	if( reason == INVALID )
+	{
+		errorResponse(connData, 400, "Invalid reason!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	struct ArgumentBuffer argBuffer;
+	WEB_argInit( &argBuffer );
+	
+	switch(reason)
+	{
+		case BUTTON:
+			{
+				char id_buf[40];
+				
+				int id_len = httpdFindArg(connData->getArgs, "id", id_buf, sizeof(id_buf));
+				if( id_len <= 0 )
 				{
 					errorResponse(connData, 400, "No button ID specified!");
 					return HTTPD_CGI_DONE;
 				}
-				argPos[0] = body;
-				argNum++;
-				break;
-			case SUBMIT:
+				if( WEB_addArg(&argBuffer, id_buf, id_len) )
 				{
-					if( connData->post->received < connData->post->len )
+					errorResponse(connData, 400, "Post too large!");
+					return HTTPD_CGI_DONE;
+				}
+			}
+			break;
+		case SUBMIT:
+			{
+				if( connData->post->received < connData->post->len )
+				{
+					errorResponse(connData, 400, "Post too large!");
+					return HTTPD_CGI_DONE;
+				}
+				
+				int bptr = 0;
+				
+				while( bptr < connData->post->len )
+				{
+					char * line = connData->post->buff + bptr;
+					
+					char * eo = os_strchr(line, '&' );
+					if( eo != NULL )
 					{
-						errorResponse(connData, 400, "Post too large!");
-						return HTTPD_CGI_DONE;
+						*eo = 0;
+						bptr = eo - connData->post->buff + 1;
+					}
+					else
+					{
+						eo = line + os_strlen( line );
+						bptr = connData->post->len;
 					}
 					
-					int bptr = 0;
+					int len = os_strlen(line);
+					while( len >= 1 && ( line[len-1] == '\r' || line[len-1] == '\n' ))
+						len--;
+					line[len] = 0;
 					
-					while( bptr < connData->post->len )
+					char * val = os_strchr(line, '=');
+					if( val != NULL )
 					{
-						if( argNum >= MAX_VARS )
-						{
-							errorResponse(connData, 400, "Too many variables!");
-							return HTTPD_CGI_DONE;
-						}
+						*val = 0;
+						char * name = line;
+						int vblen = os_strlen(val+1) * 2;
+						char value[vblen];
+						httpdUrlDecode(val+1, strlen(val+1), value, vblen);
 						
-						char * line = connData->post->buff + bptr;
+						int namLen = os_strlen(name);
+						int valLen = os_strlen(value);
 						
-						char * eo = os_strchr(line, '&' );
-						if( eo != NULL )
-						{
-							*eo = 0;
-							bptr = eo - connData->post->buff + 1;
-						}
-						else
-						{
-							eo = line + os_strlen( line );
-							bptr = connData->post->len;
-						}
-						
-						int len = os_strlen(line);
-						while( len >= 1 && ( line[len-1] == '\r' || line[len-1] == '\n' ))
-							len--;
-						line[len] = 0;
+						char arg[namLen + valLen + 3];
+						int argPtr = 0;
+						arg[argPtr++] = (char)WEB_STRING;
+						os_strcpy( arg + argPtr, name );
+						argPtr += namLen;
+						arg[argPtr++] = 0;
+						os_strcpy( arg + argPtr, value );
+						argPtr += valLen;
 						
-						char * val = os_strchr(line, '=');
-						if( val != NULL )
+						if( WEB_addArg(&argBuffer, arg, argPtr) )
 						{
-							*val = 0;
-							char * name = line;
-							int vblen = os_strlen(val+1) * 2;
-							char value[vblen];
-							httpdUrlDecode(val+1, strlen(val+1), value, vblen);
-							
-							int namLen = os_strlen(name);
-							int valLen = os_strlen(value);
-							
-							int totallen = namLen + valLen + 2;
-							if( bodyPtr + totallen > sizeof(body) - 10 )
-							{
-								errorResponse(connData, 400, "Post too large!");
-								return HTTPD_CGI_DONE;
-							}
-							
-							argPos[argNum] = body + bodyPtr;
-							
-							body[bodyPtr++] = (char)WEB_STRING;
-							os_strcpy( body + bodyPtr, name );
-							bodyPtr += namLen;
-							body[bodyPtr++] = 0;
-							
-							os_strcpy( body + bodyPtr, value );
-							bodyPtr += valLen;
-							
-							argLen[argNum++] = totallen;
+							errorResponse(connData, 400, "Post too large!");
+							return HTTPD_CGI_DONE;
 						}
 					}
 				}
-				break;
-			case LOAD:
-			case REFRESH:
-			default:
-				break;
-		}
+			}
+			break;
+		case LOAD:
+		case REFRESH:
+		default:
+			break;
+	}
+	
+	if( WEB_addArg(&argBuffer, NULL, 0) )
+	{
+		errorResponse(connData, 400, "Post too large!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	os_printf("Web callback to MCU: %s\n", reasonBuf);
+	
+	WEB_sendArgBuffer(&argBuffer, connData, (uint32_t)cb->callback, reason );
+	
+	if( reason == SUBMIT )
+	{
+		httpdStartResponse(connData, 204);
+		httpdEndHeaders(connData);
+		return HTTPD_CGI_DONE;
+	}
+	
+	return HTTPD_CGI_MORE;
+}
+
+// this method receives SLIP data from MCU sends JSON to the browser
+static int ICACHE_FLASH_ATTR WEB_handleMCUResponse(HttpdConnData *connData, CmdRequest * response)
+{
+	char jsonBuf[1500];
+	int  jsonPtr = 0;
+	
+	
+	jsonBuf[jsonPtr++] = '{';
+	
+	int c = 2;
+	while( c++ < cmdGetArgc(response) )
+	{
+		int len = cmdArgLen(response);
+		char buf[len+1];
+		buf[len] = 0;
 		
-		os_printf("Web callback to MCU: %s\n", reasonBuf);
+		cmdPopArg(response, buf, len);
 		
-		cmdResponseStart(CMD_WEB_REQ_CB, (uint32_t)cb->callback, 4 + argNum);
-		uint16_t r = (uint16_t)reason;
-		cmdResponseBody(&r, sizeof(uint16_t));
-		cmdResponseBody(&connData->conn->proto.tcp->remote_ip, 4);
-		cmdResponseBody(&connData->conn->proto.tcp->remote_port, sizeof(uint16_t));
-		cmdResponseBody(connData->url, os_strlen(connData->url));
+		if(len == 0)
+			break; // last argument
 		
-		int j;
-		for( j=0; j < argNum; j++ )
-			cmdResponseBody(argPos[j], argLen[j]);
+		if( c > 3 ) // skip the first argument
+			jsonBuf[jsonPtr++] = ',';
 		
-		cmdResponseEnd();
-	
-		if( reason == SUBMIT )
+		if( jsonPtr + 20 + len > sizeof(jsonBuf) )
 		{
-			httpdStartResponse(connData, 204);
-			httpdEndHeaders(connData);
+			errorResponse(connData, 500, "Response too large!");
 			return HTTPD_CGI_DONE;
 		}
 		
-		connData->cgiData = (void *)1;
-	}
-	
-	if( connData->cgiResponse != NULL ) // data from MCU
-	{
-		char jsonBuf[1500];
-		int  jsonPtr = 0;
+		WebValueType type = (WebValueType)buf[0];
 		
+		int nameLen = os_strlen(buf+1);
+		jsonBuf[jsonPtr++] = '"';
+		os_memcpy(jsonBuf + jsonPtr, buf + 1, nameLen);
+		jsonPtr += nameLen;
+		jsonBuf[jsonPtr++] = '"';
+		jsonBuf[jsonPtr++] = ':';
 		
-		jsonBuf[jsonPtr++] = '{';
-		CmdRequest * req = (CmdRequest *)(connData->cgiResponse);
+		char * value = buf + 2 + nameLen;
 		
-		int c = 2;
-		while( c++ < cmdGetArgc(req) )
+		switch(type)
 		{
-			int len = cmdArgLen(req);
-			char buf[len+1];
-			buf[len] = 0;
-			
-			cmdPopArg(req, buf, len);
-			
-			if(len == 0)
-				break; // last argument
-			
-			if( c > 3 ) // skip the first argument
-				jsonBuf[jsonPtr++] = ',';
-			
-			if( jsonPtr + 20 + len > sizeof(jsonBuf) )
-			{
-				errorResponse(connData, 500, "Response too large!");
-				return HTTPD_CGI_DONE;
-			}
-			
-			WebValueType type = (WebValueType)buf[0];
-			
-			int nameLen = os_strlen(buf+1);
-			jsonBuf[jsonPtr++] = '"';
-			os_memcpy(jsonBuf + jsonPtr, buf + 1, nameLen);
-			jsonPtr += nameLen;
-			jsonBuf[jsonPtr++] = '"';
-			jsonBuf[jsonPtr++] = ':';
-			
-			char * value = buf + 2 + nameLen;
-			
-			switch(type)
-			{
-				case WEB_NULL:
-					os_memcpy(jsonBuf + jsonPtr, "null", 4);
+			case WEB_NULL:
+				os_memcpy(jsonBuf + jsonPtr, "null", 4);
+				jsonPtr += 4;
+				break;
+			case WEB_INTEGER:
+				{
+					int v;
+					os_memcpy( &v, value, 4);
+					
+					char intbuf[20];
+					os_sprintf(intbuf, "%d", v);
+					os_strcpy(jsonBuf + jsonPtr, intbuf);
+					jsonPtr += os_strlen(intbuf);
+				}
+				break;
+			case WEB_BOOLEAN:
+				if( *value ) {
+					os_memcpy(jsonBuf + jsonPtr, "true", 4);
 					jsonPtr += 4;
-					break;
-				case WEB_INTEGER:
-					{
-						int v;
-						os_memcpy( &v, value, 4);
-						
-						char intbuf[20];
-						os_sprintf(intbuf, "%d", v);
-						os_strcpy(jsonBuf + jsonPtr, intbuf);
-						jsonPtr += os_strlen(intbuf);
-					}
-					break;
-				case WEB_BOOLEAN:
-					if( *value ) {
-						os_memcpy(jsonBuf + jsonPtr, "true", 4);
-						jsonPtr += 4;
-					} else {
-						os_memcpy(jsonBuf + jsonPtr, "false", 5);
-						jsonPtr += 5;
-					}
-					break;
-				case WEB_FLOAT:
-					{
-						float f;
-						os_memcpy( &f, value, 4);
-						
-						char intbuf[20];
-						os_sprintf(intbuf, "%f", f);
-						os_strcpy(jsonBuf + jsonPtr, intbuf);
-						jsonPtr += os_strlen(intbuf);
-					}
-					break;
-				case WEB_STRING:
-					jsonBuf[jsonPtr++] = '"';
-					while(*value)
-					{
-						if( *value == '\\' || *value == '"' )
-							jsonBuf[jsonPtr++] = '\\';
-						jsonBuf[jsonPtr++] = *(value++);
-					}
-					jsonBuf[jsonPtr++] = '"';
-					break;
-				case WEB_JSON:
-					os_memcpy(jsonBuf + jsonPtr, value, len - 2 - nameLen);
-					jsonPtr += len - 2 - nameLen;
-					break;
-			}
+				} else {
+					os_memcpy(jsonBuf + jsonPtr, "false", 5);
+					jsonPtr += 5;
+				}
+				break;
+			case WEB_FLOAT:
+				{
+					float f;
+					os_memcpy( &f, value, 4);
+					
+					char intbuf[20];
+					os_sprintf(intbuf, "%f", f);
+					os_strcpy(jsonBuf + jsonPtr, intbuf);
+					jsonPtr += os_strlen(intbuf);
+				}
+				break;
+			case WEB_STRING:
+				jsonBuf[jsonPtr++] = '"';
+				while(*value)
+				{
+					if( *value == '\\' || *value == '"' )
+						jsonBuf[jsonPtr++] = '\\';
+					jsonBuf[jsonPtr++] = *(value++);
+				}
+				jsonBuf[jsonPtr++] = '"';
+				break;
+			case WEB_JSON:
+				os_memcpy(jsonBuf + jsonPtr, value, len - 2 - nameLen);
+				jsonPtr += len - 2 - nameLen;
+				break;
 		}
-		
-		jsonBuf[jsonPtr++] = '}';
-		
-		noCacheHeaders(connData, 200);
-		httpdHeader(connData, "Content-Type", "application/json");
-		
-		char cl[16];
-		os_sprintf(cl, "%d", jsonPtr);
-		httpdHeader(connData, "Content-Length", cl);
-		httpdEndHeaders(connData);
-		
-		httpdSend(connData, jsonBuf, jsonPtr);
-		return HTTPD_CGI_DONE;
 	}
 	
+	jsonBuf[jsonPtr++] = '}';
+	
+	noCacheHeaders(connData, 200);
+	httpdHeader(connData, "Content-Type", "application/json");
+	
+	char cl[16];
+	os_sprintf(cl, "%d", jsonPtr);
+	httpdHeader(connData, "Content-Length", cl);
+	httpdEndHeaders(connData);
+	
+	httpdSend(connData, jsonBuf, jsonPtr);
+	return HTTPD_CGI_DONE;
+}
+
+// this method is responsible for the MCU <==JSON==> Browser communication
+int ICACHE_FLASH_ATTR WEB_CgiJsonHook(HttpdConnData *connData)
+{
+	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
+	
+	void * cgiData = connData->cgiData;
+	
+	if( cgiData == NULL )
+	{
+		connData->cgiData = (void *)1; // indicate, that request was processed
+		return WEB_handleJSONRequest(connData);
+	}
+	
+	if( connData->cgiResponse != NULL ) // data from MCU
+		return WEB_handleMCUResponse(connData, (CmdRequest *)(connData->cgiResponse));
+	
 	return HTTPD_CGI_MORE;
 }
 
+// this method is called when MCU transmits WEB_DATA command
 void ICACHE_FLASH_ATTR WEB_Data(CmdPacket *cmd)
 {
 	CmdRequest req;
@@ -373,14 +441,14 @@ void ICACHE_FLASH_ATTR WEB_Data(CmdPacket *cmd)
 	if (cmdGetArgc(&req) < 2) return;
 	
 	uint8_t ip[4];
-	cmdPopArg(&req, ip, 4);
+	cmdPopArg(&req, ip, 4);    // pop the IP address
 	
 	uint16_t port;
-	cmdPopArg(&req, &port, 2);
+	cmdPopArg(&req, &port, 2); // pop the HTTP port
 	
-	HttpdConnData * conn = httpdLookUpConn(ip, port);
-	if( conn != NULL && conn->cgi == WEB_CgiJsonHook ) // make sure that the right CGI handler will be called
+	HttpdConnData * conn = httpdLookUpConn(ip, port);  // look up connection based on IP/port
+	if( conn != NULL && conn->cgi == WEB_CgiJsonHook ) // make sure that the right CGI handler is configured
 		httpdSetCGIResponse( conn, &req );
 	else
-		os_printf("WEB response ignored as no valid http connection found for the request!\n");
+		os_printf("WEB_DATA ignored as no valid HTTP connection found!\n");
 }
diff --git a/web-server/web-server.h b/web-server/web-server.h
index 2e3413a..0827229 100644
--- a/web-server/web-server.h
+++ b/web-server/web-server.h
@@ -8,22 +8,22 @@
 
 typedef enum
 {
-  LOAD=0,
-  REFRESH,
-  BUTTON,
-  SUBMIT,
+  LOAD=0,        // loading web-page content at the first time
+  REFRESH,       // loading web-page subsequently
+  BUTTON,        // HTML button pressed
+  SUBMIT,        // HTML form is submitted
 
   INVALID=-1,
 } RequestReason;
 
 typedef enum
 {
-  WEB_STRING=0,
-  WEB_NULL,
-  WEB_INTEGER,
-  WEB_BOOLEAN,
-  WEB_FLOAT,
-  WEB_JSON
+  WEB_STRING=0,  // the value is string
+  WEB_NULL,      // the value is NULL
+  WEB_INTEGER,   // the value is integer
+  WEB_BOOLEAN,   // the value is boolean
+  WEB_FLOAT,     // the value is float
+  WEB_JSON       // the value is JSON data
 } WebValueType;
 
 void   WEB_Init();