(function ($) {

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

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

            var $this = $(this),
                minHeight = $this.height();

            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);