I'm using ScrollMagic and Greensock but it gets stuck scrolling

Question

I'm using ScrollMagic and Greensock to create a "scroll to" feature, where the user clicks on a link in a persistent navigation, then the view is scrolled to the specified section down the page (a long page full of content and images). But in Safari (v 7.0.1), it scrolls fine about 80% of the time, the rest of the time, it gets stuck part way down scrolling to the selected section. It doesn't even look like it's getting stuck on some significant part of the page, it just gets hung in between seemingly random chunks of the page.

The content on the page is confidential, so I can't share the whole page, but I can share the script that's driving it. Am I doing anything wrong in the script that would cause it to get hung up part way through a scroll?

$(document).ready(function($) {
                            // build tween
                            var tween1 = new TimelineMax ()
                                .add([
                                    TweenMax.fromTo("#trigger1 .image1", 1, {scale: 1, autoAlpha: 1, top: 1200}, {top: -1630, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger1 .image2", 1, {scale: 1, autoAlpha: 1, top: 1300}, {top: -560, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger1 .image3", 1, {scale: 1, autoAlpha: 1, top: 1200}, {top: -1630, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger1 .image6", 1, {scale: 1, autoAlpha: 1, top: 1200}, {top: -1630, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger1 .image4", 1, {scale: 1, autoAlpha: 1, top: 1300}, {top: -560, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger1 .image5", 1, {scale: 1, autoAlpha: 0.3, top: 1200}, {top: -1600, ease: Linear.easeNone})
                                ]);

                            // build scene
                            var scene1 = new ScrollScene({triggerElement: "#point1", duration: $(window).height()})
                                            .setTween(tween1)
                                            .addTo(controller);

                            // show indicators (requires debug extension)
                            //scene.addIndicators();






                            //Processing

                            var tween2 = new TimelineMax ()
                                .add([
                                    TweenMax.fromTo("#trigger2 .image1", 1, {scale: 1, autoAlpha: 1, top: 900}, {top: -1330, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger2 .image4", 1, {scale: 1, autoAlpha: 1, top: 900}, {top: -440, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger2 .image5", 1, {scale: 1, autoAlpha: 0.3, top: 1200}, {top: -1600, ease: Linear.easeNone})
                                ]);

                            // build scene
                            var scene2 = new ScrollScene({triggerElement: "#point2", duration: $(window).height()})
                                            .setTween(tween2)
                                            .addTo(controller);







                            //Imaging
                            var tween3 = new TimelineMax ()
                                .add([
                                    TweenMax.fromTo("#trigger3 .image3", 1, {scale: 1, autoAlpha: 1, top: 900}, {top: -950, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger3 .image4", 1, {scale: 1, autoAlpha: 1, top: 1300}, {top: -960, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger3 .image5", 1, {scale: 1, autoAlpha: 0.3, top: 1200}, {top: -1600, ease: Linear.easeNone})
                                ]);

                            // build scene
                            var scene3 = new ScrollScene({triggerElement: "#point3", duration: $(window).height()})
                                            .setTween(tween3)
                                            .addTo(controller);






                            //Advanced Imaging

                            var tween4 = new TimelineMax ()
                                .add([
                                    TweenMax.fromTo("#trigger4 .image1", 1, {scale: 1, autoAlpha: 1, top: 1100}, {top: -1150, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger4 .image2", 1, {scale: 1, autoAlpha: 1, top: 1300}, {top: -890, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger4 .image5", 1, {scale: 1, autoAlpha: 0.3, top: 1200}, {top: -1600, ease: Linear.easeNone})
                                ]);

                            // build scene
                            var scene4 = new ScrollScene({triggerElement: "#point4", duration: $(window).height()})
                                            .setTween(tween4)
                                            .addTo(controller);






                            //Reservoir Services



                            var tween5 = new TimelineMax ()
                                .add([
                                    TweenMax.fromTo("#trigger5 .image1", 1, {scale: 1, autoAlpha: 1, top: 900}, {top: -900, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger5 .image2", 1, {scale: 1, autoAlpha: 1, top: 1100}, {top: -340, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger5 .image3", 1, {scale: 1, autoAlpha: 1, top: 1000}, {top: -240, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger5 .image4", 1, {scale: 1, autoAlpha: 1, top: 900}, {top: -140, ease: Linear.easeNone}),
                                    TweenMax.fromTo("#trigger5 .image5", 1, {scale: 1, autoAlpha: 0.3, top: 1200}, {top: -1600, ease: Linear.easeNone})
                                ]);

                            // build scene
                            var scene5 = new ScrollScene({triggerElement: "#point5", duration: $(window).height()})
                                            .setTween(tween5)
                                            .addTo(controller);







                            //Resize fixer

                            $(window).on("resize", function () {
                                // update duration.
                                scene1.duration($(window).innerHeight());
                                scene2.duration($(window).innerHeight());
                                scene3.duration($(window).innerHeight());
                                scene4.duration($(window).innerHeight());
                                scene5.duration($(window).innerHeight());
                            });






                        });

Answer 1

I stumbled over this problem as well and I think this is a bug in Safari.
What I suspect happens is: Animations that change the size of the DOM during scrolling trigger a scroll event to the browser, because it changes the relations within the scrollbar.
This in turn makes the programmatic scroll stop, because it's designed to cancel once the user scrolls on is own during the scroll Animation.
Imagine a 10 second scroll from top to bottom and you have no way of cancelling it. That's just bad UX and this is why it cancels.

But to keep Safari from stopping the scroll without any apparent reason the only solution I found is to force TweenMax not to cancel the scroll animation.
Use this code:

TweenLite.to(window, 1, {scrollTo:{y:300, autoKill:false}});

You can read more about it here:
http://forums.greensock.com/topic/7205-scrollto-bug-in-182-in-safari-602-mountain-lion

I think this solution is all right as long as you make your scroll animation very short.

EDIT: Another solution might be using this:
http://www.bytemuse.com/scrollIt.js/

Also next time feel free to post your question in the ScrollMagic github issues section, which I check more frequently. :)

hope this helps.
regards,
J