js代码

<script src="js/polyfill.min.js"></script>
<script>
let hero = document.getElementById('hero-slides');
let menu = document.getElementById('menu');
let slides = document.getElementById('slides');
let next = [ 'next', 'next-catch' ].map(n => document.getElementById(n));
let prev = [ 'prev', 'prev-catch' ].map(n => document.getElementById(n));
let slideChildren = slides.children;
let slideCount = slides.children.length;
let currentlyDemoing = false;
let currentPage = 0;
let slidesPerPage = () => window.innerWidth > 1700 ? 4 : window.innerWidth > 1200 ? 3 : 2;
let maxPageCount = () => slideCount / slidesPerPage() - 1;

function goToPage(pageNumber = 0) {
	currentPage = Math.min(maxPageCount(), Math.max(0, pageNumber));
	console.log(currentPage);
	hero.style.setProperty('--page', currentPage);
}

function sleep(time) {
	return new Promise(res => setTimeout(res, time));
}

function hoverSlide(index) {
	index in slideChildren &&
		slideChildren[index].classList.add('hover');
}

function unhoverSlide(index) {
	index in slideChildren &&
		slideChildren[index].classList.remove('hover');
}

async function demo() {
	if(currentlyDemoing) {
		return;
	}
	currentlyDemoing = true;
	if(currentPage !== 0) {
		goToPage(0);
		await sleep(800);
	}
	let slides = slidesPerPage();
	let pageSeq_ = { 2: [ 1, 2, 1 ], 3: [ 1, 2, 1 / 3 ], 4: [ 1, 1, 0 ] };
	let pageSeq = pageSeq_[slides] || pageSeq_[4];
	let slideSeq_ = { 2: [ 2, 4, 3 ], 3: [ 3, 6, 2 ], 4: [ 3, 6, 2 ] };
	let slideSeq = slideSeq_[slides] || slideSeq_[2];
	await sleep(300);
	goToPage(pageSeq[0]);
	await sleep(500);
	hoverSlide(slideSeq[0]);
	await sleep(1200);
	goToPage(pageSeq[1]);
	unhoverSlide(slideSeq[0]);
	await sleep(500);
	hoverSlide(slideSeq[1]);
	await sleep(1200);
	goToPage(pageSeq[2]);
	unhoverSlide(slideSeq[1]);
	await sleep(300);
	hoverSlide(slideSeq[2]);
	await sleep(1600);
	goToPage(0);
	unhoverSlide(slideSeq[2]);
	currentlyDemoing = false;
}

next.forEach(n => n.addEventListener('click', () => !currentlyDemoing && goToPage(currentPage + 1)));
prev.forEach(n => n.addEventListener('click', () => !currentlyDemoing && goToPage(currentPage - 1)));
menu.addEventListener('click', demo);

sleep(100).then(demo);

// window.addEventListener('resize', () => {
	// console.log(document.body.style.getPropertyValue('--slide-per-page'));
// });</script>