Cleanup and simplify JS code

Change-Id: I393e22763c1a1d18878026bf459b747b150429fb
diff --git a/dev/js/src/vc.js b/dev/js/src/vc.js
index 4772115..1e6a91c 100644
--- a/dev/js/src/vc.js
+++ b/dev/js/src/vc.js
@@ -60,7 +60,7 @@
   KorAP._validStringMatchRE = new RegExp("^(?:eq|ne|contains(?:not)?|excludes)$");
   KorAP._overrideStyles     = false;
 
-  var loc = KorAP.Locale;
+  const loc = KorAP.Locale;
 
   KorAP._vcKeyMenu = undefined;
   KorAP._vcDatePicker = dpClass.create();