meituan

 //根据屏幕大小及dpi调整缩放和大小
        (function() {
            var scale = 1.0;
            var ratio = 1;
            if (window.devicePixelRatio >= 2) {
                scale *= 0.5;
                ratio *= 2;
            }
            var text = '<meta name="viewport" content="initial-scale=' + scale + ', maximum-scale=' + scale +', minimum-scale=' + scale + ', width=device-width, user-scalable=no" />';
            document.write(text);
            document.documentElement.style.fontSize = 50*ratio + "px";
   })();