window.onload = function () {
    window.onscroll = scroll;
    // 固定导航背景颜色
    var scroll = function () {
        var nav_height = document.getElementById("top_nav");
        var scrollTop =document.body.scrollTop || document.documentElement.scrollTop;
        if (scrollTop > 0) {
            nav_height.classList.add('header_scroll')
        } else {
            nav_height.classList.remove('header_scroll')
        }
    }
    scroll()
    // 导航动画
    var nav = document.getElementsByClassName("nav")[0];
    var click_a = nav.getElementsByTagName("a");
    for (let i = 0; i < click_a.length; i++) {
        click_a[i].index = i;
        click_a[i].onclick = function () {
            for (let a = 0; a < click_a.length; a++) {
                click_a[a].classList.remove("choosed")
            }
            click_a[this.index].classList.add("choosed")
        }
    }
    // 导航条滚动加载样式
    function home_scroll() {
        let scrollTop = document.documentElement.scrollTop || document.body.scrollTop
        let home_one = document.getElementById("top").offsetTop - 90
        let home_two = document.getElementById("introduce").offsetTop - 90
        let home_three = document.getElementById("department").offsetTop - 90
        let home_four = document.getElementById("cours").offsetTop - 90
        let home_five = document.getElementById("product_service").offsetTop - 90
        let nav = document.getElementsByClassName("nav")[0];
        let click_a = nav.getElementsByTagName("a");
        for (let i = 0; i < click_a.length; i++) {
            click_a[i].classList.remove("choosed")
            switch (true) {
                case scrollTop < home_two:
                    click_a[0].classList.add("choosed")
                    break;
                case scrollTop >= home_two && scrollTop < home_three:
                    click_a[1].classList.add("choosed")
                    break;
                case scrollTop >= home_three && scrollTop < home_four:
                    click_a[2].classList.add("choosed")
                    break;
                case scrollTop >= home_four && scrollTop < home_five:
                    click_a[3].classList.add("choosed")
                    break;
                case scrollTop >= home_five:
                    click_a[4].classList.add("choosed")
                    break;
            }
        }
    }
    home_scroll()
    window.onscroll = function () {
        home_scroll()
        scroll()
    }

    // 公司介绍品牌切换
    var first = document.getElementsByClassName("first_introduce")[0];
    var second = document.getElementsByClassName("second_introduce")[0];
    second.onclick = function () {
        this.style.right = "30px";
        this.style.animation = "smallBig .6s  ease forwards";
        this.style.zIndex = "5";
        first.style.left = "-30px";
        first.style.zIndex = "4";
        first.style.animation = "bigSmall .6s  ease forwards";
    }
    first.onclick = function () {
        this.style.left = 0;
        this.style.animation = "toInit2 .6s  ease forwards";
        this.style.zIndex = "5";
        second.style.right = 0;
        second.style.zIndex = "4";
        second.style.animation = "toInit .6s  ease forwards";
    }
    // 侧边导航代码执行
    common();
}