diff --git a/script/single.js b/script/single.js
index 7e1f885..1d80fa9 100644
--- a/script/single.js
+++ b/script/single.js
@@ -1,9 +1,9 @@
 (function() {
 'use strict';
 
-let mainfig  = document.getElementById('mainfig');
-let mainimg  = document.getElementById('mainimg');
-let mainlink = document.getElementById('mainlink');
+let mainfig;
+let mainimg;
+let mainlink;
 
 function openCW(caption, focusLink) {
   mainfig.removeChild(caption);
@@ -48,6 +48,10 @@ function activateButton(button) {
 }
 
 function setup() {
+  mainfig  = document.getElementById('mainfig');
+  mainimg  = document.getElementById('mainimg');
+  mainlink = document.getElementById('mainlink');
+
   for (let button of document.querySelectorAll('#alts input')) {
     button.onchange = e => { if (button.checked) activateButton(button); };
   }