jira.add-diffs.html

<script type="text/javascript">
(function($){
    var matches = location.pathname.match(/browse\/([A-Z]+-[0-9]+)/);
    if (matches) {
        $(document).ready(function() {

            /*
             * Add diffs to change logs
             */
            var script = document.createElement('script');
            script.src = 'https://google-diff-match-patch.googlecode.com/svn/trunk/javascript/diff_match_patch.js';

            var para = /&para;/g, description = /\s*Description\s*/, brs = /<br><br>/g;

            script.onload = function() {

                var dmp = new diff_match_patch;
                dmp.Diff_Timeout = 1;
                dmp.Diff_EditCost = 6;

                $('.changehistory').each(function(){
                    var row = $(this);
                    
                    if (!description.test(row.find('.activity-name').text())) return;

                    var oldContainer = row.find('.activity-old-val'),
                        newContainer = row.find('.activity-new-val'),
                        oldVal = oldContainer.text(),
                        newVal = newContainer.text();

                    //create diff
                    var diff = dmp.diff_main(oldVal, newVal);
                    dmp.diff_cleanupEfficiency(diff);
                    var diffHtml = dmp.diff_prettyHtml(diff).replace(para, '').replace(brs, '<br>');

                    newContainer.html(diffHtml);
                });
            };

            document.documentElement.appendChild(script);
        });
    }
})(jQuery);
</script>