window.addEventListener('scroll', handleScroll, true)
handleScroll()

function handleScroll() {
    if (window.scrollY > 100) {
        document.getElementsByClassName('handler-app-android-download').item(0).className = "handler-app-android-download"
        document.getElementsByClassName("handler-to-top").item(0).style.display = "block"
    } else {
        document.getElementsByClassName('handler-app-android-download').item(0).className = "handler-app-android-download handler-item-bottom"
        document.getElementsByClassName("handler-to-top").item(0).style.display = "none"
    }
}

function ToTop() {
    window.scrollTo({
        top: 0,
        behavior: 'smooth'
    })
}

//todo 首页轮播图
window.onload = function () {
    var items = document.getElementsByClassName("item");
    var circles = document.getElementsByClassName("circle");
    var leftBtn = document.getElementById("btn-left");
    var rightBtn = document.getElementById("btn-right");
    var content = document.querySelector('.content');
    var index = 0;
    var timer = null;

//清除class
    var clearclass = function () {
        for (let i = 0; i < items.length; i++) {
            items[i].className = "item";
            circles[i].className = "circle";
            circles[i].setAttribute("num", i);
        }
    }

    /*只显示一个class*/
    function move() {
        clearclass();
        items[index].className = "item active";
        circles[index].className = "circle white";
    }

//点击右边按钮切换下一张图片
    rightBtn.onclick = function () {
        if (index === items.length - 1){
            index = 0;
        }else {
            index++
        }
        move();
    }
//点击左边按钮切换上一张图片
    leftBtn.onclick = function () {
        if (index === 0){
            index = items.length - 1;
        }else {
            index--
        }
        move();
    }
//开始定时器，点击右边按钮，实现轮播
    rightBtn.onclick();
    timer = setInterval(function () {
        rightBtn.onclick();
    }, 3000)
//点击圆点时，跳转到对应图片
    for (var i = 0; i < circles.length; i++) {
        circles[i].addEventListener("click", function () {
            var point_index = this.getAttribute("num");
            index = point_index;
            move();
        })

    }
//鼠标移入清除定时器，并开启一个三秒的定时器，使慢慢转动
    content.onmouseover = function () {
        clearInterval(timer);
        timer = setInterval(function () {
            rightBtn.onclick();
        }, 3000)
    }
//鼠标移出又开启定时器
    content.onmouseleave = function () {
        clearInterval(timer);
        timer = setInterval(function () {
            rightBtn.onclick();
        }, 1500)
    }
}