Update split.js

split.js

@@ -32,6 +32,9 @@ function fixDragBtn() {
 
     var wrapper = document.getElementById("right-area-wrapper");
     var transcript = document.querySelector(`[data-tt-transcript="0"]`);
+
+    if (transcript == null) return;
+  
     var wrapper_rec = wrapper.getBoundingClientRect();
     var transcript_rec= transcript.getBoundingClientRect();
     h = wrapper_rec.height - (transcript_rec.top - wrapper_rec.top);