diff --git a/phpBB/assets/javascript/core.js b/phpBB/assets/javascript/core.js
index 37728864c4..a70e6b3e9a 100644
--- a/phpBB/assets/javascript/core.js
+++ b/phpBB/assets/javascript/core.js
@@ -7,6 +7,7 @@ phpbb.alertTime = 100;
 
 // define a couple constants for keydown functions.
 var keymap = {
+	TAB: 9,
 	ENTER: 13,
 	ESC: 27
 };