nfywt-wx/wx.demo.ywtinfo.com/js/asset/zepto-slide-transition.min.js

/* Zepto plugin : slide transition v1.0 */
(function ($) {

    /* SlideDown */
    $.fn.slideDown = function (duration) {

        // get the element position to restore it then
        var position = this.css('position');

        // show element if it is hidden
        this.show();

        // place it so it displays as usually but hidden
        this.css({
            position: 'absolute',
            visibility: 'hidden'
        });

        // get naturally height, margin, padding
        var marginTop = this.css('margin-top');
        var marginBottom = this.css('margin-bottom');
        var paddingTop = this.css('padding-top');
        var paddingBottom = this.css('padding-bottom');
        var height = this.css('height');

        // set initial css for animation
        this.css({
            position: position,
            visibility: 'visible',
            overflow: 'hidden',
            height: 0,
            marginTop: 0,
            marginBottom: 0,
            paddingTop: 0,
            paddingBottom: 0
        });

        // animate to gotten height, margin and padding
        this.animate({
            height: height,
            marginTop: marginTop,
            marginBottom: marginBottom,
            paddingTop: paddingTop,
            paddingBottom: paddingBottom
        }, duration);

    };

    /* SlideUp */
    $.fn.slideUp = function (duration) {

        // active the function only if the element is visible
        if (this.height() > 0) {

            var target = this;

            // get the element position to restore it then
            var position = target.css('position');

            // get the element height, margin and padding to restore them then
            var height = target.css('height');
            var marginTop = target.css('margin-top');
            var marginBottom = target.css('margin-bottom');
            var paddingTop = target.css('padding-top');
            var paddingBottom = target.css('padding-bottom');

            // set initial css for animation
            this.css({
                visibility: 'visible',
                overflow: 'hidden',
                height: height,
                marginTop: marginTop,
                marginBottom: marginBottom,
                paddingTop: paddingTop,
                paddingBottom: paddingBottom
            });

            // animate element height, margin and padding to zero
            target.animate({
                    height: 0,
                    marginTop: 0,
                    marginBottom: 0,
                    paddingTop: 0,
                    paddingBottom: 0
                },
                {
                    // callback : restore the element position, height, margin and padding to original values
                    duration: duration,
                    queue: false,
                    complete: function(){
                        target.hide();
                        target.css({
                            visibility: 'visible',
                            overflow: 'hidden',
                            height: height,
                            marginTop: marginTop,
                            marginBottom: marginBottom,
                            paddingTop: paddingTop,
                            paddingBottom: paddingBottom
                        });
                    }
                });
        }
    };

    /* SlideToggle */
    $.fn.slideToggle = function (duration) {

        // if the element is hidden, slideDown !
        if (this.height() == 0) {
            this.slideDown(duration);
        }
        // if the element is visible, slideUp !
        else {
            this.slideUp(duration);
        }
    };

})(Zepto);