jquery.testimonials.js

(function ($){
    $.fn.testimonials = function(options) {
        var list_wrapper = this;
        var children = this.children();
        var list = [];
        var display_count = options.display;
        var current_index = 0;
        var timer = options.timer; 
        var animate = options.animate;
        
        init();

        function init() {
            // setup css
            var animation = 'opacity ' + animate + 'ms, max-height ' + animate + 'ms, margin-bottom ' + animate + 'ms';
            $(children).css({
                WebkitTransition : animation,
                MozTransition    : animation,
                MsTransition     : animation,
                OTransition      : animation,
                transition       : animation
            });

            // setup list
            for (var i = 0; i < children.length; i++) {
                list.push(children[i]);
                if (i % 2 === 0) {
                    $(list[i]).addClass('even');
                } else {
                    $(list[i]).addClass('odd');
                }
            }
            
            $(list_wrapper)
                // set height of wrapper
                .height(getMaxHeight())
                // remove contents of wrapper
                .empty()
                // set class of loaded
                .addClass('loaded');

            // display initial list items
            for (var i = 0; i < display_count; i++) {
                list_wrapper.append(list[i]);
                setTimeout(function(){
                    $(list_wrapper).children().addClass('visible')
                }, 1);
            }

            // activate loop
            setInterval(loop, options.timer);
        }

        // the loop
        function loop() {
            var prev = getPrev();
            var next = getNext();

            // remove hidden item
            $(list[prev]).removeClass('hidden').remove();
            // append next item and animate it
            list_wrapper.append(list[next]);
            setTimeout(function(){
                $(list_wrapper).children().last().addClass('visible')
            }, options.animate / 2);
            // hide the first item
            $(list[current_index]).addClass('hidden').removeClass('visible');
            // iterate the current_index
            iterate();
        }

        // returns array with current visible elements ex. [0, 1]
        function getVisible() {
            var output = [];

            for (var i = 0; i < display_count; i++) {
                var index = current_index + i;
                if (index >= list.length) {
                    index -= list.length;
                }
                output.push(list[index]);
            }

            return output;
        };

        // returns element before current index
        function getPrev() {
            var output = current_index - 1;     
            if (output < 0) {
                output = list.length - 1;
            }     

            return output;
        };

        // returns next element to be appended
        function getNext() {
            var output = current_index + display_count;
            if (output >= list.length) {
                output -= list.length;
            }

            return output;
        }

        // iterates the current index
        function iterate() {
            current_index++;
            if (current_index >= list.length) {
                current_index -= list.length;
            }
        };

        // returns the maximum possible height based on list items height and the display_count
        function getMaxHeight() {
            var output = [];
            var max = 0;

            for (var i = 0; i < list.length; i++) {
                var height = 0;
                for (var e = 0; e < display_count; e++) {
                    var index = i + e;
                    if (index >= list.length) {
                        index -= list.length;
                    }
                    height += $(list[index]).outerHeight(true);
                }
                if (height > max) {
                    max = height;
                }
            }

            return max;
        }
    }
})(jQuery);