diff --git a/lib/jsdom/level2/html.js b/lib/jsdom/level2/html.js
index <HASH>..<HASH> 100644
--- a/lib/jsdom/level2/html.js
+++ b/lib/jsdom/level2/html.js
@@ -798,7 +798,7 @@ define('HTMLOptionElement', {
       return closest(this, 'FORM');
     },
     get defaultSelected() {
-      return !!this.getAttribute('selected');
+      return this.getAttribute('selected') !== null;
     },
     set defaultSelected(s) {
       if (s) this.setAttribute('selected', 'selected');
Fix selected attribute

The element <option selected=""> is selected.