fix bug

Author: taisukef

cr.js

@@ -1,6 +1,6 @@
 export const cr = (tag, parent, cls) => {
   const c = document.createElement(tag);
-  if (cls) t.className = cls;
+  if (cls) c.className = cls;
   if (parent) parent.appendChild(c);
   return c;
 };