diff --git a/jerry-core/api/jerry.c b/jerry-core/api/jerry.c
index fead23d14..0f253148c 100644
--- a/jerry-core/api/jerry.c
+++ b/jerry-core/api/jerry.c
@@ -389,7 +389,10 @@ jerry_parse_named_resource (const jerry_char_t *name_p, /**< name (usually a fil
 #ifdef JERRY_DEBUGGER
   if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
   {
-    jerry_debugger_send_string (JERRY_DEBUGGER_SOURCE_CODE_NAME, name_p, name_length);
+    jerry_debugger_send_string (JERRY_DEBUGGER_SOURCE_CODE_NAME,
+                                JERRY_DEBUGGER_NO_SUBTYPE,
+                                name_p,
+                                name_length);
   }
 #else /* JERRY_DEBUGGER */
   JERRY_UNUSED (name_p);
diff --git a/jerry-core/debugger/debugger.c b/jerry-core/debugger/debugger.c
index accab4f30..ea6a5d266 100644
--- a/jerry-core/debugger/debugger.c
+++ b/jerry-core/debugger/debugger.c
@@ -160,7 +160,7 @@ jerry_debugger_send_eval (const lit_utf8_byte_t *eval_string_p, /**< evaluated s
   }
 
   ecma_value_t message = result;
-  uint8_t type = JERRY_DEBUGGER_EVAL_RESULT;
+  uint8_t type = JERRY_DEBUGGER_EVAL_OK;
 
   if (ECMA_IS_VALUE_ERROR (result))
   {
@@ -183,7 +183,8 @@ jerry_debugger_send_eval (const lit_utf8_byte_t *eval_string_p, /**< evaluated s
         ecma_free_value (result);
 
         const lit_utf8_byte_t *string_p = lit_get_magic_string_utf8 (id);
-        return jerry_debugger_send_string (JERRY_DEBUGGER_EVAL_ERROR,
+        return jerry_debugger_send_string (JERRY_DEBUGGER_EVAL_RESULT,
+                                           type,
                                            string_p,
                                            strlen ((const char *) string_p));
       }
@@ -201,7 +202,7 @@ jerry_debugger_send_eval (const lit_utf8_byte_t *eval_string_p, /**< evaluated s
   ecma_string_t *string_p = ecma_get_string_from_value (message);
 
   ECMA_STRING_TO_UTF8_STRING (string_p, buffer_p, buffer_size);
-  bool success = jerry_debugger_send_string (type, buffer_p, buffer_size);
+  bool success = jerry_debugger_send_string (JERRY_DEBUGGER_EVAL_RESULT, type, buffer_p, buffer_size);
   ECMA_FINALIZE_UTF8_STRING (buffer_p, buffer_size);
 
   ecma_free_value (message);
@@ -702,6 +703,7 @@ jerry_debugger_send_data (jerry_debugger_header_type_t type, /**< message type *
  */
 bool
 jerry_debugger_send_string (uint8_t message_type, /**< message type */
+                            uint8_t sub_type, /**< subtype of the string */
                             const uint8_t *string_p, /**< string data */
                             size_t string_length) /**< length of string */
 {
@@ -728,10 +730,19 @@ jerry_debugger_send_string (uint8_t message_type, /**< message type */
     string_p += max_fragment_len;
   }
 
+  if (sub_type != JERRY_DEBUGGER_NO_SUBTYPE)
+  {
+    string_length += 1;
+  }
+
   JERRY_DEBUGGER_SET_SEND_MESSAGE_SIZE (message_string_p, 1 + string_length);
   message_string_p->type = (uint8_t) (message_type + 1);
 
   memcpy (message_string_p->string, string_p, string_length);
+  if (sub_type != JERRY_DEBUGGER_NO_SUBTYPE)
+  {
+    message_string_p->string[string_length - 1] = sub_type;
+  }
 
   return jerry_debugger_send (sizeof (jerry_debugger_send_type_t) + string_length);
 } /* jerry_debugger_send_string */
@@ -960,6 +971,7 @@ jerry_debugger_send_exception_string (ecma_value_t exception_value) /**< error v
   ECMA_STRING_TO_UTF8_STRING (string_p, string_data_p, string_size);
 
   bool result = jerry_debugger_send_string (JERRY_DEBUGGER_EXCEPTION_STR,
+                                            JERRY_DEBUGGER_NO_SUBTYPE,
                                             string_data_p,
                                             string_size);
 
diff --git a/jerry-core/debugger/debugger.h b/jerry-core/debugger/debugger.h
index 5244866f7..d60ad2a0a 100644
--- a/jerry-core/debugger/debugger.h
+++ b/jerry-core/debugger/debugger.h
@@ -33,6 +33,11 @@
  */
 #define JERRY_DEBUGGER_TIMEOUT 100
 
+/**
+  * This constant represents that the string to be sent has no subtype.
+  */
+#define JERRY_DEBUGGER_NO_SUBTYPE 0
+
 /**
  * Limited resources available for the engine, so it is important to
  * check the maximum buffer size. It needs to be between 64 and 256 bytes.
@@ -114,8 +119,6 @@ typedef enum
   JERRY_DEBUGGER_BACKTRACE_END = 20, /**< last backtrace data */
   JERRY_DEBUGGER_EVAL_RESULT = 21, /**< eval result */
   JERRY_DEBUGGER_EVAL_RESULT_END = 22, /**< last part of eval result */
-  JERRY_DEBUGGER_EVAL_ERROR = 23, /**< eval result when an error is occured */
-  JERRY_DEBUGGER_EVAL_ERROR_END = 24, /**< last part of eval result when an error is occured */
 
   /* Messages sent by the client to server. */
 
@@ -139,6 +142,15 @@ typedef enum
   JERRY_DEBUGGER_EVAL_PART = 13, /**< next message of evaluating a string */
 } jerry_debugger_header_type_t;
 
+/**
+  * Subtypes of send_eval.
+  */
+typedef enum
+{
+  JERRY_DEBUGGER_EVAL_OK = 1, /**< eval result, no error */
+  JERRY_DEBUGGER_EVAL_ERROR = 2, /**< eval result when an error is occured */
+} jerry_debugger_eval_subtype_t;
+
 /**
  * Delayed free of byte code data.
  */
@@ -318,7 +330,7 @@ void jerry_debugger_breakpoint_hit (uint8_t message_type);
 void jerry_debugger_send_type (jerry_debugger_header_type_t type);
 bool jerry_debugger_send_configuration (uint8_t max_message_size);
 void jerry_debugger_send_data (jerry_debugger_header_type_t type, const void *data, size_t size);
-bool jerry_debugger_send_string (uint8_t message_type, const uint8_t *string_p, size_t string_length);
+bool jerry_debugger_send_string (uint8_t message_type, uint8_t sub_type, const uint8_t *string_p, size_t string_length);
 bool jerry_debugger_send_function_cp (jerry_debugger_header_type_t type, ecma_compiled_code_t *compiled_code_p);
 bool jerry_debugger_send_parse_function (uint32_t line, uint32_t column);
 void jerry_debugger_send_memstats (void);
diff --git a/jerry-core/parser/js/js-parser-statm.c b/jerry-core/parser/js/js-parser-statm.c
index 74cc42935..d0f1f2549 100644
--- a/jerry-core/parser/js/js-parser-statm.c
+++ b/jerry-core/parser/js/js-parser-statm.c
@@ -406,6 +406,7 @@ parser_parse_function_statement (parser_context_t *context_p) /**< context */
   if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
   {
     jerry_debugger_send_string (JERRY_DEBUGGER_FUNCTION_NAME,
+                                JERRY_DEBUGGER_NO_SUBTYPE,
                                 name_p->u.char_p,
                                 name_p->prop.length);
 
diff --git a/jerry-core/parser/js/js-parser.c b/jerry-core/parser/js/js-parser.c
index 5c8316b84..6724c7847 100644
--- a/jerry-core/parser/js/js-parser.c
+++ b/jerry-core/parser/js/js-parser.c
@@ -2194,6 +2194,7 @@ parser_parse_function (parser_context_t *context_p, /**< context */
     if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
     {
       jerry_debugger_send_string (JERRY_DEBUGGER_FUNCTION_NAME,
+                                  JERRY_DEBUGGER_NO_SUBTYPE,
                                   context_p->lit_object.literal_p->u.char_p,
                                   context_p->lit_object.literal_p->prop.length);
     }
@@ -2489,7 +2490,10 @@ parser_parse_script (const uint8_t *source_p, /**< source code */
 #ifdef JERRY_DEBUGGER
   if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
   {
-    jerry_debugger_send_string (JERRY_DEBUGGER_SOURCE_CODE, source_p, size);
+    jerry_debugger_send_string (JERRY_DEBUGGER_SOURCE_CODE,
+                                JERRY_DEBUGGER_NO_SUBTYPE,
+                                source_p,
+                                size);
   }
 #endif /* JERRY_DEBUGGER */
 
diff --git a/jerry-debugger/jerry-client-ws.html b/jerry-debugger/jerry-client-ws.html
index 37f7106d5..1b5484b40 100644
--- a/jerry-debugger/jerry-client-ws.html
+++ b/jerry-debugger/jerry-client-ws.html
@@ -35,6 +35,7 @@ textarea {
   <div>
 </div>
 <script>
+// Messages sent by the server to client.
 var JERRY_DEBUGGER_CONFIGURATION = 1;
 var JERRY_DEBUGGER_PARSE_ERROR = 2;
 var JERRY_DEBUGGER_BYTE_CODE_CP = 3;
@@ -57,9 +58,12 @@ var JERRY_DEBUGGER_BACKTRACE = 19;
 var JERRY_DEBUGGER_BACKTRACE_END = 20;
 var JERRY_DEBUGGER_EVAL_RESULT = 21;
 var JERRY_DEBUGGER_EVAL_RESULT_END = 22;
-var JERRY_DEBUGGER_EVAL_ERROR = 23;
-var JERRY_DEBUGGER_EVAL_ERROR_END = 24;
 
+// Subtypes of eval
+var JERRY_DEBUGGER_EVAL_OK = 1;
+var JERRY_DEBUGGER_EVAL_ERROR = 2;
+
+// Messages sent by the client to server.
 var JERRY_DEBUGGER_FREE_BYTE_CODE_CP = 1;
 var JERRY_DEBUGGER_UPDATE_BREAKPOINT = 2;
 var JERRY_DEBUGGER_EXCEPTION_CONFIG = 3;
@@ -855,7 +859,7 @@ function DebuggerClient(address)
                   + (breakpoint.at ? "at " : "around ")
                   + breakpointInfo
                   + breakpointToString(breakpoint));
-                  
+
         if (debuggerObj.display)
         {
           debuggerObj.printSource(debuggerObj.display);
@@ -896,19 +900,18 @@ function DebuggerClient(address)
 
       case JERRY_DEBUGGER_EVAL_RESULT:
       case JERRY_DEBUGGER_EVAL_RESULT_END:
-      case JERRY_DEBUGGER_EVAL_ERROR:
-      case JERRY_DEBUGGER_EVAL_ERROR_END:
       {
         evalResult = concatUint8Arrays(evalResult, message);
-
-        if (message[0] == JERRY_DEBUGGER_EVAL_RESULT_END)
+        var subType = evalResult[evalResult.length - 1];
+        evalResult = evalResult.slice(0, -1);
+        if (subType == JERRY_DEBUGGER_EVAL_OK)
         {
           appendLog(cesu8ToString(evalResult));
           evalResult = null;
           return;
         }
 
-        if (message[0] == JERRY_DEBUGGER_EVAL_ERROR_END)
+        if (subType == JERRY_DEBUGGER_EVAL_ERROR)
         {
           appendLog("Uncaught exception: " + cesu8ToString(evalResult));
           evalResult = null;
diff --git a/jerry-debugger/jerry-client-ws.py b/jerry-debugger/jerry-client-ws.py
index 49182cd92..4a6189d9e 100755
--- a/jerry-debugger/jerry-client-ws.py
+++ b/jerry-debugger/jerry-client-ws.py
@@ -48,8 +48,10 @@ JERRY_DEBUGGER_BACKTRACE = 19
 JERRY_DEBUGGER_BACKTRACE_END = 20
 JERRY_DEBUGGER_EVAL_RESULT = 21
 JERRY_DEBUGGER_EVAL_RESULT_END = 22
-JERRY_DEBUGGER_EVAL_ERROR = 23
-JERRY_DEBUGGER_EVAL_ERROR_END = 24
+
+# Subtypes of eval
+JERRY_DEBUGGER_EVAL_OK = 1
+JERRY_DEBUGGER_EVAL_ERROR = 2
 
 
 # Messages sent by the client to server.
@@ -1064,17 +1066,16 @@ def main():
             prompt.cmdloop()
 
         elif buffer_type in [JERRY_DEBUGGER_EVAL_RESULT,
-                             JERRY_DEBUGGER_EVAL_RESULT_END,
-                             JERRY_DEBUGGER_EVAL_ERROR,
-                             JERRY_DEBUGGER_EVAL_ERROR_END]:
+                             JERRY_DEBUGGER_EVAL_RESULT_END]:
 
             message = b""
             eval_type = buffer_type
             while True:
                 message += data[3:]
 
-                if buffer_type in [JERRY_DEBUGGER_EVAL_RESULT_END,
-                                   JERRY_DEBUGGER_EVAL_ERROR_END]:
+                if buffer_type == JERRY_DEBUGGER_EVAL_RESULT_END:
+                    subtype = ord(message[-1])
+                    message = message[:-1]
                     break
 
                 data = debugger.get_message(True)
@@ -1085,7 +1086,7 @@ def main():
                                        eval_type + 1]:
                     raise Exception("Eval result expected")
 
-            if buffer_type == JERRY_DEBUGGER_EVAL_ERROR_END:
+            if subtype == JERRY_DEBUGGER_EVAL_ERROR:
                 print("Uncaught exception: %s" % (message))
             else:
                 print(message)