gsap 事件

 1 ScrollTrigger.create({
 2         trigger: '.box',
 3         start: 'top top',
 4         end: '+=2000',
 5         markers: true,
 6         scrub: true,
 7         pin: true,
 8         animation:
 9             gsap.timeline().to('.box1', {
10                 scale: 1.5, borderRadius: '50%',background:'blue'
11                 , onStart() {
12                     console.log('start');
13                 },
14                 onComplete() {
15                     console.log('ended');
16                 },
17                 onReverseComplete() {
18                     console.log('reverse ended');
19                 }
20             }),
21         onUpdate(e) {
22             console.log(e.progress) // 0.5;
23         },
24         onEnter: () => {
25             console.log('滚动到start位置触发')
26         },
27         onEnterBack: () => {
28             console.log('滚动超过end位置，再进入滚动区域触发')
29         },
30         onLeave: () => {
31             console.log('滚出end位置时触发')
32         },
33         onLeaveBack: () => {
34             console.log('滚出end位置，再滚回来超过start位置触发')
35         },
36     })