nizongfeng
/
ZZCS

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <meta name="viewport" content="initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">
    <style>
        html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, em, p, font, img, small, strong, center, dl, dt, dd, ol, ul, li, form, label, table, caption, tbody, tr, th, td {margin:0;padding:0;border:0;outline:0;font-size:12px;vertical-align:baseline} 
        ol, ul {list-style:none} :focus {outline:none; } 
        table {border-collapse:collapse;border-spacing: 0} 
        caption, th, td { text-align: left; font-weight: normal} 
        strong {font-weight:600} 
        a{font:12px Arial;text-decoration:none;color:#404040;cursor:pointer;} 
        a:hover{text-decoration:underline;color:#FF3300} 
        h1{font-size:16px;font-weight:600;color:#666} .left{float:left} .right{float:right} .clear{clear:both}


    </style>
</head>
<script>
    ;(function(win, lib) {
        var doc = win.document;
        var docEl = doc.documentElement;
        var metaEl = doc.querySelector('meta[name="viewport"]');
        var flexibleEl = doc.querySelector('meta[name="flexible"]');
        var dpr = 0;
        var scale = 0;
        var tid;
        var flexible = lib.flexible || (lib.flexible = {});

        if (metaEl) {
            console.warn('将根据已有的meta标签来设置缩放比例');
            var match = metaEl.getAttribute('content').match(/initial\-scale=([\d\.]+)/);
            if (match) {
                scale = parseFloat(match[1]);
                dpr = parseInt(1 / scale);
            }
        } else if (flexibleEl) {
            var content = flexibleEl.getAttribute('content');
            if (content) {
                var initialDpr = content.match(/initial\-dpr=([\d\.]+)/);
                var maximumDpr = content.match(/maximum\-dpr=([\d\.]+)/);
                if (initialDpr) {
                    dpr = parseFloat(initialDpr[1]);
                    scale = parseFloat((1 / dpr).toFixed(2));    
                }
                if (maximumDpr) {
                    dpr = parseFloat(maximumDpr[1]);
                    scale = parseFloat((1 / dpr).toFixed(2));    
                }
            }
        }

        if (!dpr && !scale) {
            var isAndroid = win.navigator.appVersion.match(/android/gi);
            var isIPhone = win.navigator.appVersion.match(/iphone/gi);
            var devicePixelRatio = win.devicePixelRatio;
            if (isIPhone) {
            // iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
            if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {                
                dpr = 3;
            } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)){
                dpr = 2;
            } else {
                dpr = 1;
            }
        } else {
            // 其他设备下，仍旧使用1倍的方案
            dpr = 1;
        }
        scale = 1 / dpr;
    }

    docEl.setAttribute('data-dpr', dpr);
    if (!metaEl) {
        metaEl = doc.createElement('meta');
        metaEl.setAttribute('name', 'viewport');
        metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');
        if (docEl.firstElementChild) {
            docEl.firstElementChild.appendChild(metaEl);
        } else {
            var wrap = doc.createElement('div');
            wrap.appendChild(metaEl);
            doc.write(wrap.innerHTML);
        }
    }

    function refreshRem(){
        var width = docEl.getBoundingClientRect().width;
        if (width / dpr > 540) {
            width = 540 * dpr;
        }
        var rem = width / 10;
        docEl.style.fontSize = rem + 'px';
        flexible.rem = win.rem = rem;
    }

    win.addEventListener('resize', function() {
        clearTimeout(tid);
        tid = setTimeout(refreshRem, 300);
    }, false);
    win.addEventListener('pageshow', function(e) {
        if (e.persisted) {
            clearTimeout(tid);
            tid = setTimeout(refreshRem, 300);
        }
    }, false);

    if (doc.readyState === 'complete') {
        doc.body.style.fontSize = 12 * dpr + 'px';
    } else {
        doc.addEventListener('DOMContentLoaded', function(e) {
            doc.body.style.fontSize = 12 * dpr + 'px';
        }, false);
    }
    

    refreshRem();

    flexible.dpr = win.dpr = dpr;
    flexible.refreshRem = refreshRem;
    flexible.rem2px = function(d) {
        var val = parseFloat(d) * this.rem;
        if (typeof d === 'string' && d.match(/rem$/)) {
            val += 'px';
        }
        return val;
    }
    flexible.px2rem = function(d) {
        var val = parseFloat(d) / this.rem;
        if (typeof d === 'string' && d.match(/px$/)) {
            val += 'rem';
        }
        return val;
    }

})(window, window['lib'] || (window['lib'] = {}));
</script>

<body>
<span style="font-size:10rem; background:#e60012;">大</span>
<div style="width: 10rem; background:#e60112;">大</div>
<div style="width: 100%; background:#e60212;">大</div>
<div style="font-size:10rem;width: 10rem; background:#e60312;">大</div>

</body>
</html>