Update transcript-tracer.js

transcript-tracer.js

@@ -645,9 +645,9 @@ function handleSelection() {
   }
 
   // This could still be `undefined`.
-  var endWordIndexForTime = endWordIndexForTime.dataset.ttWord;
+  var endWordIndexForTime = endWordElementForTime.dataset.ttWord;
   // Let's get the `listIndex`.
-  var endWordListIndexForTime = endWordIndexForTime.listIndex;
+  var endWordListIndexForTime = endWordElementForTime.listIndex;
 
   var endSeconds = null;  
   if (endWordIndexForTime !== undefined) {