//字体设置
     (function(doc, win) {
        var docEl = doc.documentElement,
            isIOS = navigator.userAgent.match(/iphone|ipod|ipad/gi),
            dpr = isIOS ? Math.min(win.devicePixelRatio, 3) : 1,
            dpr = window.top === window.self ? dpr : 1, //被iframe引用时，禁止缩放
            dpr = 1, // 首页引用IFRAME，强制为1
            scale = 1 / dpr,
            resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
        docEl.dataset.dpr = win.devicePixelRatio;
        if (navigator.userAgent.match(/iphone/gi) && screen.width == 375 && win.devicePixelRatio == 2) {
            docEl.classList.add('iphone6')
        }
        if (navigator.userAgent.match(/iphone/gi) && screen.width == 414 && win.devicePixelRatio == 3) {
            docEl.classList.add('iphone6p')
        }
        var metaEl = doc.createElement('meta');
        metaEl.name = 'viewport';
        metaEl.content = 'initial-scale=' + scale + ',maximum-scale=' + scale + ', minimum-scale=' + scale;
        docEl.firstElementChild.appendChild(metaEl);
        var recalc = function() {
            var width = docEl.clientWidth;
            if (width / dpr > 640) {
                width = 640 * dpr;
            }
            docEl.style.fontSize = 100 * (width / 640) + 'px';
        };
        recalc()
        if (!doc.addEventListener) return;
        // win.addEventListener(resizeEvt, recalc, false);
    })(document, window);