(function($) {

   /*
   * Auto-growing textareas; technique ripped from Facebook
   */
   $.fn.autogrow = function(options) {

      this.filter('textarea').each(function() {

         var $this = $(this),
                minHeight = $this.height(),
                lineHeight = $this.css('lineHeight');

         var shadow = $('<div></div>').css({
            position: 'absolute',
            top: -10000,
            left: -10000,
            width: $(this).width() - parseInt($this.css('paddingLeft')) - parseInt($this.css('paddingRight')),
            fontSize: $this.css('fontSize'),
            fontFamily: $this.css('fontFamily'),
            lineHeight: $this.css('lineHeight'),
            resize: 'none'
         }).appendTo(document.body);

         var update = function() {

            var times = function(string, number) {
               for (var i = 0, r = ''; i < number; i++) r += string;
               return r;
            };

            var val = this.value.replace(/</g, '&lt;')
                                    .replace(/>/g, '&gt;')
                                    .replace(/&/g, '&amp;')
                                    .replace(/\n$/, '<br/>&nbsp;')
                                    .replace(/\n/g, '<br/>')
                                    .replace(/ {2,}/g, function(space) { return times('&nbsp;', space.length - 1) + ' ' });

            shadow.html(val);
            $(this).css('height', Math.max(shadow.height() + 20, minHeight));

         }

         $(this).change(update).keyup(update).keydown(update);

         update.apply(this);

      });

      return this;

   }

})(jQuery);