habitica/app/views/shared/_progressbar.erb

<% if current_user %>
  <div id="progressbar" style="width:30%;">
    <span id="tnl">(Level <%= current_user.lvl %>)&nbsp;&nbsp;&nbsp;<%= current_user.exp.to_i.to_s + "/" + current_user.tnl.to_i.to_s %></span>
  </div>
  <script>
  $(function() {
    $( "#progressbar" ).progressbar({
      value: <%= (current_user.exp/current_user.tnl) * 100 %>
    });
  });
  </script>
<% end %>