diff --git a/core/client.js b/core/client.js
index 88f62b01..cfa111fc 100644
--- a/core/client.js
+++ b/core/client.js
@@ -835,7 +835,7 @@ window.addEventListener("load", function() {
 				description.innerText = tag.dataset.tip;
 				tooltip.appendChild(description);
 			}
-			var parts = tag.accessKeyLabel.split('+');
+			var parts = tag.accessKeyLabel ? tag.accessKeyLabel.split('+') : [];
 			for (var i = 0; i < parts.length; i++)
 			{
 				var key = parts[i];