TypedJS

Add this line to your application's Gemfile:

gem 'typedJS'

And then execute:

$ bundle

Or install it yourself as:

$ gem install typedJS

In your JavaScript manifest (e.g. application.js)

//= require typed

In your Stylesheet manifest (e.g. application.css)

//= require blink

<script>
  $(function(){
      $(".element").typed({
        strings: ["First sentence.", "Second sentence."],
        typeSpeed: 0
      });
  });
</script>
...

<span class="element"></span>