Untitled

<!DOCTYPE html>
<html>
<head>
<script src="https://code.jquery.com/jquery-2.1.1.min.js"></script>
  <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" type="text/css" />
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body>
<div class="well clearfix">
    <textarea class="form-control"></textarea><br>
    <span>140</span>
    <button class="js-tweet-button btn btn-primary pull-right" disabled>Tweet</button>
    <button class="js-add-photo-button btn btn-default pull-right">Add Photo</button>
  </div>
</body>
</html>

$("textarea").on("input", update);

$(".js-add-photo-button").on("click", function() {
  if ($(this).hasClass("is-on"))
    $(this).removeClass("is-on").text("Add Photo");
  else
    $(this).addClass("is-on").text("? Photo Added");
  update();
});

function update() {
  var extra = ($(".js-add-photo-button").hasClass("is-on") ? 23 : 0);
  $("span").text(140 - extra - $("textarea").val().length);

  var disabled = !($("textarea").val().length > 0 || $(".js-add-photo-button").hasClass("is-on"));
  $(".js-tweet-button").prop("disabled", disabled);
}