Improved version of Image Comparison Slider from CodyHouse http://codyhouse.co/gem/css-jquery-image-comparison-slider/

main.js

// improved drags function, replace it in your code
function drags(dragElement, resizeElement, container, labelContainer, labelResizeElement) {
    var $ = jQuery;

    dragElement.on('mousedown vmousedown', function (e) {
        dragElement.addClass('cd-draggable');
        resizeElement.addClass('cd-resizable');

        var dragWidth = dragElement.outerWidth(),
            xPosition = dragElement.offset().left + dragWidth - e.pageX,
            containerOffset = container.offset().left,
            containerWidth = container.outerWidth(),
            minLeft = containerOffset + 10,
            maxLeft = containerOffset + containerWidth - dragWidth - 10;

        dragElement.parent().bind('mousemove.cd vmousemove.cd', function (e) {
            var leftValue = e.pageX + xPosition - dragWidth;

            // constrain the draggable element to move inside his container
            if (leftValue < minLeft) {
                leftValue = minLeft;
            } else if (leftValue > maxLeft) {
                leftValue = maxLeft;
            }

            var widthValue = (leftValue + dragWidth / 2 - containerOffset) * 100 / containerWidth + '%';

            $('.cd-draggable', container).css('left', widthValue).one('mouseup vmouseup', function () {
                $(this).removeClass('cd-draggable');
                resizeElement.removeClass('cd-resizable');
            });

            $('.cd-resizable', container).css('width', widthValue);

            updateLabel(labelResizeElement, resizeElement, 'left');
            updateLabel(labelContainer, resizeElement, 'right');

        }).one('mouseup vmouseup', function (e) {
            dragElement.removeClass('cd-draggable');
            resizeElement.removeClass('cd-resizable');

            dragElement.parent().unbind('mousemove.cd vmousemove.cd');
        });

        e.preventDefault();

    }).on('mouseup vmouseup', function (e) {
        dragElement.removeClass('cd-draggable');
        resizeElement.removeClass('cd-resizable');
    });
}

This is terrific 👍 thanks again