Don't re-run OCR if no file provided, closes #6

Author: simonw

ocr.html

@@ -314,6 +314,10 @@ <h2>Pages</h2>
   const textareas = document.querySelectorAll('.image-container textarea');
   const images = document.querySelectorAll('.image-container img');
 
+  if (!textareas.length) {
+    return;
+  }
+
   // Blank all the textareas
   Array.from(textareas).forEach(ta => ta.value = '');
   showFullDocument();