Diff by worlds. Based on https://code.google.com/p/google-diff-match-patch/wiki/LineOrWordDiffs

diff_linesToWords_.js

// Based on https://code.google.com/p/google-diff-match-patch/wiki/LineOrWordDiffs.
diff_match_patch.prototype.diff_linesToWords_ = function(text1, text2) {
  var lineArray = [];
  var lineHash = {};

  lineArray[0] = '';

  function diff_linesToCharsMunge_(text) {
    var chars = '';
    var lineStart = 0;
    var lineEnd = -1;
    var lineArrayLength = lineArray.length;
    var line;

    while (lineEnd < text.length - 1) {
      // Everything that is not a word symbol - is a separator.
      lineEnd = text.substring(lineStart).search(/[^\w]/);

      if (lineEnd == -1) {
        lineEnd = text.length - 1;
      } else {
        lineEnd += lineStart;
      }

      // Do not include separator symbols in line.
      if (lineStart === lineEnd) {
        line = text.substring(lineStart, lineEnd + 1);
        lineStart = lineEnd + 1;
      } else {
        line = text.substring(lineStart, lineEnd);
        lineStart = lineEnd;
      }

      try {

      // NOTE if you have hasOwnProperty in lineHash - then you are going to call on number and get a message like this:
      // if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) : (lineHash[
      //                                              ^
      // TypeError: number is not a function

      // if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) : (lineHash[line] !== undefined)) {
      if (lineHash[line] !== undefined) {
        chars += String.fromCharCode(lineHash[line]);
      } else {
        chars += String.fromCharCode(lineArrayLength);
        lineHash[line] = lineArrayLength;
        lineArray[lineArrayLength++] = line;
      }
        } catch (ex) {
            console.log(lineHash.hasOwnProperty, lineHash);
        }
    }
    return chars;
  }

  var chars1 = diff_linesToCharsMunge_(text1);
  var chars2 = diff_linesToCharsMunge_(text2);
  return {chars1: chars1, chars2: chars2, lineArray: lineArray};
};

// ----------------------------------------------------------------------------------------------------------------- //
// Then you can calculate diff like this:

var a = dmp.diff_linesToWords_(text1, text2);

var lineText1 = a['chars1'];
var lineText2 = a['chars2'];
var lineArray = a['lineArray'];

diff = dmp.diff_main(lineText1, lineText2, false);
dmp.diff_charsToLines_(diff, lineArray);