Re-work the document scoping.

src/core.js

@@ -12,9 +12,6 @@ var jQuery = function( selector, context ) {
 	// Map over the $ in case of overwrite
 	_$ = window.$,
 
-	// Use the correct document accordingly with window argument (sandbox)
-	//document = window.document,
-
 	// A central reference to the root jQuery(document)
 	rootjQuery,
 

src/intro.js

@@ -15,3 +15,5 @@
  */
 (function( window, undefined ) {
 
+// Use the correct document accordingly with window argument (sandbox)
+var document = window.document;