 type, txt) {
                    let span = document.createElement('span');
                    span.appendChild(document
                        .createTextNode(txt));
                    if (type == 'added') {
                        span.style.color = 'green';
                        span.style.background = 'lightgreen';
                    } else if (type == 'removed') {
                        span.style.color = 'red';
                        span.style.background = '#fbb';
                    } else 