diff --git a/lib/components/ModalPortal.js b/lib/components/ModalPortal.js
index 88d9a116..5faec109 100644
--- a/lib/components/ModalPortal.js
+++ b/lib/components/ModalPortal.js
@@ -169,7 +169,7 @@ var ModalPortal = module.exports = React.createClass({
     return !this.props.isOpen && !this.state.beforeClose;
   },
 
-  contentHasFocus() {
+  contentHasFocus: function() {
     return document.activeElement === this.refs.content || this.refs.content.contains(document.activeElement);
   },