Simple jQuery Plugin that auto resizes text to fill a specific sized div (great for responsive slideshows that utilize large banner text with variable lengths), derived from https://gist.github.com/iam4x/5015270

autoSizr.js

$.fn.autoSizr = function () {
  var el, elements, _i, _len, _results;
  elements = $(this);
  if (elements.length < 0) {
    return;
  }
  _results = [];
  for (_i = 0, _len = elements.length; _i < _len; _i++) {
    el = elements[_i];
    _results.push((function(el) {
      var resizeText, _results1;
      resizeText = function() {
        var elNewFontSize;
        elNewFontSize = (parseInt($(el).css('font-size').slice(0, -2)) - 1) + 'px';
        return $(el).css('font-size', elNewFontSize);
      };
      _results1 = [];
      while (el.scrollHeight > el.offsetHeight) {
        _results1.push(resizeText());
      }
      return _results1;
    })(el));
  }
  return $(this); 
};

To make this grow and shink here is a simple hack on line 10. Crude but works for my use case. 200px may be extreme in some cases.

$.fn.autoSizr = function () {
	var el, elements, _i, _len, _results;
	elements = $(this);
	if (elements.length < 0) {
		return;
	}
	_results = [];
	for (_i = 0, _len = elements.length; _i < _len; _i++) {
		el = elements[_i];
		$(el).css({'font-size' : '200px'})
		_results.push((function(el) {
		var resizeText, _results1;
		resizeText = function() {
			var elNewFontSize;
			elNewFontSize = (parseInt($(el).css('font-size').slice(0, -2)) - 1) + 'px';
			return $(el).css('font-size', elNewFontSize);
		};
		_results1 = [];
		while (el.scrollHeight > el.offsetHeight) {
			_results1.push(resizeText());
		}
		return _results1;
		})(el));
	}
	return $(this); 
	};

Usage:

$('#myDivId').autoSizr();