diff --git a/ui/jquery.ui.tabs.js b/ui/jquery.ui.tabs.js
index 4c850b98e..5bb544889 100644
--- a/ui/jquery.ui.tabs.js
+++ b/ui/jquery.ui.tabs.js
@@ -427,7 +427,7 @@ $.widget( "ui.tabs", {
 		// meta-function to give users option to provide a href string instead of a numerical index.
 		// also sanitizes numerical indexes to valid values.
 		if ( typeof index == "string" ) {
-			index = this.anchors.index( this.anchors.filter( "[href$=" + index + "]" ) );
+			index = this.anchors.index( this.anchors.filter( "[href$='" + index + "']" ) );
 		}
 
 		return index;