Core: Handle IE11 bug with document.activeElement in iframes

Fixes #11539
Closes gh-1518

diff --git a/ui/core.js b/ui/core.js
index eaf11d0a82b76dbf299a7c85505074467466cd49..a8167d68318397d36aed2bb5662296b7bed35206 100644 (file)
--- a/ui/core.js
+++ b/ui/core.js
@@ -63,6 +63,13 @@ $.extend( $.ui, {
                        activeElement = document.body;
                }
 
+               // Support: IE 11 only
+               // IE11 returns a seemingly empty object in some cases when accessing
+               // document.activeElement from an <iframe>
+               if ( !activeElement.nodeName ) {
+                       activeElement = document.body;
+               }
+
                return activeElement;
        },