var app = document.getElementById('app');
var typewriter = new Typewriter(app, {
loop: true
});
typewriter.typeString('Hello World!')
.pauseFor(2500)
.deleteAll()
.typeString('Strings can be removed')
.pauseFor(2500)
.deleteChars(7)
.typeString('altered!')
.start();
<div id="app"></div>