Update transcript-tracer.js

transcript-tracer.js

@@ -491,7 +491,9 @@ function handleWordClick(e) {
   }
 
   // pause
-  ttActivePlayer.pause()
+  if (ttActivePlayer != null) {
+    ttActivePlayer.pause()
+  }
   
 }
 
@@ -524,7 +526,9 @@ function handleWordDBClick(e) {
   }
 
   // pause
-  ttActivePlayer.play()
+  if (ttActivePlayer != null) {
+    ttActivePlayer.play()
+  }
 }