diff --git a/readme.md b/readme.md
index 56214fa..91d58fe 100644
--- a/readme.md
+++ b/readme.md
@@ -113,10 +113,10 @@ WebOS, Windows [Phone/Mobile], Zenwalk, ...
 <!doctype html>
 <html>
 <head>
-<script type="text/javascript" src="ua-parser.min.js"></script>
-<script type="text/javascript">
+<script src="ua-parser.min.js"></script>
+<script>
 
-	var parser = new UAParser();
+    var parser = new UAParser();
 
     // by default it takes ua string from current browser's window.navigator.userAgent
     console.log(parser.getResult());
diff --git a/src/ua-parser.js b/src/ua-parser.js
index a9e6c53..b855b77 100755
--- a/src/ua-parser.js
+++ b/src/ua-parser.js
@@ -318,8 +318,11 @@
             /xiaomi\/miuibrowser\/([\w\.]+)/i                                   // MIUI Browser
             ], [VERSION, [NAME, 'MIUI Browser']], [
 
-            /;fbav\/([\w\.]+);/i                                                // Facebook App for iOS & Android
+            /;fbav\/([\w\.]+);/i                                                // Facebook App for iOS & Android with version
             ], [VERSION, [NAME, 'Facebook']], [
+            
+            /FBAN\/FBIOS|FB_IAB\/FB4A/i                                         // Facebook App for iOS & Android without version
+            ], [[NAME, 'Facebook']], [
 
             /safari\s(line)\/([\w\.]+)/i,                                       // Line App for iOS
             /android.+(line)\/([\w\.]+)\/iab/i                                  // Line App for Android
@@ -494,6 +497,7 @@
 
             /d\/huawei([\w\s-]+)[;\)]/i,                                        // Huawei
             /android.+\s(nexus\s6p|vog-[at]?l\d\d|ane-[at]?l[x\d]\d|eml-a?l\d\da?|lya-[at]?l\d[\dc]|clt-a?l\d\di?)/i
+
             ], [MODEL, [VENDOR, 'Huawei'], [TYPE, MOBILE]], [
 
             /android.+(bah2?-a?[lw]\d{2})/i                                     // Huawei MediaPad
diff --git a/test/browser-test.json b/test/browser-test.json
index d60a50d..23dbb2e 100644
--- a/test/browser-test.json
+++ b/test/browser-test.json
@@ -310,7 +310,7 @@
         }
     },
     {
-        "desc"    : "Facebook in-App Browser for Android",
+        "desc"    : "Facebook in-App Browser for Android with version",
         "ua"      : "Mozilla/5.0 (Linux; Android 5.0; SM-G900P Build/LRX21T; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/43.0.2357.121 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/35.0.0.48.273;]",
         "expect"  :
         {
@@ -320,7 +320,7 @@
         }
     },
     {
-        "desc"    : "Facebook in-App Browser for iOS",
+        "desc"    : "Facebook in-App Browser for iOS with version",
         "ua"      : "Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Mobile/14E304 [FBAN/FBIOS;FBAV/91.0.0.41.73;FBBV/57050710;FBDV/iPhone8,1;FBMD/iPhone;FBSN/iOS;FBSV/10.3.1;FBSS/2;FBCR/Telekom.de;FBID/phone;FBLC/de_DE;FBOP/5;FBRV/0])",
         "expect"  :
         {
@@ -329,6 +329,16 @@
             "major"   : "91"
         }
     },
+    {
+        "desc"    : "Facebook in-App Browser for iOS without version",
+        "ua"      : "Mozilla/5.0 (iPhone; CPU iPhone OS 13_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 [FBAN/FBIOS;FBDV/iPhone10,2;FBMD/iPhone;FBSN/iOS;FBSV/13.3.1;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBCR/]",
+        "expect"  :
+        {
+            "name"    : "Facebook",
+            "version" : "undefined",
+            "major"   : "undefined"
+        }
+    },
     {
         "desc"    : "Falkon",
         "ua"      : "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Falkon/3.0.0 Chrome/61.0.3163.140 Safari/537.36",
