Merge #35 - Prevent TypeError: Document not active

Pull-request: #35
Fixes: #34

jquery.fullscreen.js

@@ -1,5 +1,5 @@
 /**
- * @preserve jquery.fullscreen 1.1.5
+ * @preserve jquery.fullscreen 1.1.6
  * https://github.com/kayahr/jquery-fullscreen-plugin
  * Copyright (C) 2012-2013 Klaus Reimer <[email protected]>
  * Licensed under the MIT license
@@ -61,10 +61,7 @@ function fullScreen(state)
         }
 
         // Check fullscreen state
-        state = !!doc["fullscreenElement"]
-            || !!doc["msFullscreenElement"]
-            || !!doc["webkitIsFullScreen"]
-            || !!doc["mozFullScreen"];
+        state = fullScreenState(doc);
         if (!state) return state;
 
         // Return current fullscreen element or "true" if browser doesn't
@@ -100,11 +97,21 @@ function fullScreen(state)
             || (/** @type {?Function} */ doc["webkitCancelFullScreen"])
             || (/** @type {?Function} */ doc["msExitFullscreen"])
             || (/** @type {?Function} */ doc["mozCancelFullScreen"]);
-        if (func) func.call(doc);
+        if (func && fullScreenState(doc)) func.call(doc);
         return this;
     }
 }
 
+/**
+ * Check fullscreen state
+ *
+ * @param {Document} doc The content document
+ * @return {Boolean}
+ */
+function fullScreenState(doc) {
+    return !!(doc["fullscreenElement"] || doc["msFullscreenElement"] || doc["webkitIsFullScreen"] || doc["mozFullScreen"]);
+}
+
 /**
  * Toggles the fullscreen mode.
  *