(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(),
                fontSize: $this.css('fontSize'),
                fontFamily: $this.css('fontFamily'),
                lineHeight: $this.css('lineHeight'),
                resize: 'none'
            }).appendTo(document.body);

            var update = function() {

                var val = this.value.replace(/</g, '&lt;')
                                    .replace(/>/g, '&gt;')
                                    .replace(/&/g, '&amp;')
                                    .replace(/\n/g, '<br/>');

                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);