CountDiff

// ==UserScript==
// @name     Count Diff
// @version  1
// @grant    none
// @require https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js
// ==/UserScript==

$(document).ready(function(){

  var wordCount = 0;


  if ($('td.diff-addedline').length > 0) {


      $('td.diff-addedline').each(function( index ) {


         if ($(this).find("ins").length > 0) {


           $(this).find("ins").each(function() {

             wordCount += countWords(this);

           });


                 } else {

          wordCount += countWords(this);

                }

    });

     alert("Number of added words: "+wordCount);
  }


 });

function countWords(el) {

  var cont = $(el).html();
  cont = cont.replace(/<[^>]*>/g," ");
  cont = cont.replace(/\s+/g, ' ');
  cont = cont.trim();
  var n = cont.split(" ").length;

  return n;

}