缩放

var cw=document.documentElement.clientWidth||document.body.clientWidth,ch=document.documentElement.clientHeight||document.body.clientHeight,zoom=cw/320;
        var scale;
        if((ch/cw)>(1028/640)){scale=cw/640;}
        else{scale=ch/1028}
        var cover=(640*scale)/(320*zoom)-0.1;

(function() {
    var c = document.documentElement,
    d = function() {
        var b = c.getBoundingClientRect().width;
        s = (640 <= b ? 640 : b) / 640,
        document.write('<style id="scaleCon">.o2-scale{-webkit-transform: scale(' + s + "); transform: scale(" + s + ");-webkit-transform-origin:0% 0%;transform-origin:0% 0%;}</style>");
        window.addEventListener("resize",
        function() {
            var e = c.getBoundingClientRect().width;
            s = (640 <= e ? 640 : e) / 640;
            document.getElementById("scaleCon").innerHTML = ".o2-scale{-webkit-transform: scale(" + s + "); transform: scale(" + s + ");-webkit-transform-origin:0% 0%;transform-origin:0% 0%;}"
        })
    };
    d()
})();