Expands the textarea depending on content

auto-expand-textarea.js

(function($)
{
  $(document).on('input', 'textarea', function()
  {
    var $this = $(this);
    var padTop = parseInt($this.css('padding-top'),     10);
    var padBot = parseInt($this.css('padding-bottom'),  10);
    $this.height(0);
    var scroll = $this.prop('scrollHeight');
    $this.height(scroll - padTop - padBot);
  });
})(jQuery);