Stretch text to full width of container

$('.stretch-text').each(function(index, el) {
  var line = $(el);
  line.html('<span class="stretch-it">'+line.text()+'</span>');

  var text = line.find('.stretch-it' );
  var textLength = line.text().length,
      textWidth = text.width();
  var spacing = line.width() - textWidth;

  var lt_spacing = spacing / textLength;
  line.css('letter-spacing', lt_spacing + 'px' );

});