diff --git a/Blob.js b/Blob.js
index b9648d3..7dc0313 100644
--- a/Blob.js
+++ b/Blob.js
@@ -208,4 +208,13 @@
 		return object.__proto__;
 	};
 	view.Blob.prototype = getPrototypeOf(new view.Blob());
-}(typeof self !== "undefined" && self || typeof window !== "undefined" && window || typeof global !== "undefined" && global));
+}(
+	   typeof self !== "undefined" && self
+	|| typeof window !== "undefined" && window
+	|| typeof global !== "undefined" && global 
+	|| Function('return this.content')() 
+	|| Function('return this')()
+));
+// `self` is undefined in Firefox for Android content script context
+// while `this` is nsIContentFrameMessageManager
+// with an attribute `content` that corresponds to the window