Check if hidden is available first

Author: leobrines

src/core/Stage.js

@@ -226,7 +226,11 @@ Phaser.Stage.prototype.updateTransform = function () {
 */
 Phaser.Stage.prototype.checkVisibility = function () {
 
-    if (document.webkitHidden !== undefined)
+    if (document.hidden !== undefined)
+    {
+        this._hiddenVar = 'visibilitychange';
+    }
+    else if (document.webkitHidden !== undefined)
     {
         this._hiddenVar = 'webkitvisibilitychange';
     }
@@ -238,10 +242,6 @@ Phaser.Stage.prototype.checkVisibility = function () {
     {
         this._hiddenVar = 'msvisibilitychange';
     }
-    else if (document.hidden !== undefined)
-    {
-        this._hiddenVar = 'visibilitychange';
-    }
     else
     {
         this._hiddenVar = null;