移动端meta标签的设置

var phoneWidth = parseInt(window.screen.width);

var phoneScale = phoneWidth / 640;

var ua = navigator.userAgent;

if (/Android (\d+\.\d+)/.test(ua)) {

    var version = parseFloat(RegExp.$1);

    if (version > 2.3) {

        document.write('<meta name="viewport" content="width=640, initial-scale= ' + phoneScale + " ,minimum-scale = " + phoneScale + ", maximum-scale = " + phoneScale + ', target-densitydpi=device-dpi">')

    } else {

        document.write('<meta name="viewport" content="width=640, initial-scale= ' + phoneScale + ' , target-densitydpi=device-dpi">')

    }

} else {

    document.write('<meta name="viewport" content="width=640, user-scalable=no, target-densitydpi=device-dpi">')

};