function fontSize() {
    let doc = document.documentElement,
        resizeEvt = "orientationchange" in window ? "orientationchange" : "resize",
        recalc = function () {
            let winW = doc.clientWidth,
                size;
            if (!winW) return;

            if(winW <= 480){
                size = Math.round(winW / 7.5);
            }else if (winW <= 768) {
                size = Math.round(winW / 10.5);
                if (size > 65) {
                    size = 65;
                }
            } else if(winW <= 1200){
                size = Math.round(winW / 13);
            } else if (winW <= 1800) {
                size = Math.round(winW / 16);
            } else {
                size = 100;
            };
            doc.style.fontSize = size + 'px';
        };
    if (!document.addEventListener) return;
    window.addEventListener(resizeEvt, recalc, false);
    document.addEventListener("DOMContentLoaded", recalc, false);
};
fontSize();

const userBrowser = (function () {
    const ua = navigator.userAgent;
    const testUa = function (regexp) {
        return regexp.test(ua.toLowerCase())
    };

    let userBrowserClient = function () {
        let client = '';
        if (/(iPhone|iPad|iPod|iOS)/i.test(ua)) {
            client = 'iOS';
        } else if (/(Android)/i.test(ua)) {
            client = 'Android';
        } else {
            client = 'PC';
        }
        return client;
    };
    let userBrowserType = function () {
        let shell = "none";
        let shellVs = "unknow";
        if (testUa(/micromessenger/g)) {
            shell = "wechat"; // 微信浏览器
        } else if (testUa(/qqbrowser/g)) {
            shell = "qq"; // QQ浏览器
        } else if (testUa(/ubrowser/g)) {
            shell = "uc"; // UC浏览器
        } else if (testUa(/qihu 360se/g)) {
            shell = "360"; // 360浏览器
        } else if (testUa(/2345explorer/g)) {
            shell = "2345"; // 2345浏览器
        } else if (testUa(/metasr/g)) {
            shell = "sougou"; // 搜狗浏览器
        } else if (testUa(/lbbrowser/g)) {
            shell = "liebao"; // 猎豹浏览器
        } else if (testUa(/maxthon/g)) {
            shell = "maxthon"; // 遨游浏览器
        }
        return shell
    };

    return {
        userBrowserClient: userBrowserClient,
        userBrowserType: userBrowserType
    }
})();



function dynamicLoadJs(url, callback) {
    var head = document.getElementsByTagName('head')[0];
    var script = document.createElement('script');
    script.type = 'text/javascript';
    script.src = url;
    script.defer = 'defer';
    if (typeof (callback) === 'function') {
        script.onload = script.onreadystatechange = function () {
            if (!this.readyState || this.readyState === 'loaded' || this.readyState === 'complete') {
                callback();
                script.onload = script.onreadystatechange = null;
            }
        }
    }
    head.appendChild(script);
}

if (userBrowser.userBrowserClient() == 'PC') {
    try {
        eval('()=>{}');
    } catch (eo) {
        dynamicLoadJs("js/polyfill/polyfill.min.js");
    };
};