<script type="text/javascript">
//手机淘宝参考viewport
var metaEl=doc.createElement('meta');
var scale=isRetina?0.5:1;
metaEl.setAttribute('name','viewport');
metaEl.setAttribute('content','initial-scale='+scale+',maximum-scale='+scale+',minimum-scale='+scale+',user-scalable=no');
if (docEl.firstElementChild) {
Document.DocumentElement.firstElementChild.appendChild(metaEl);
} else {
var wrap=doc.createElement('div');
wrap.appendChild(metaEl);
Document.write(wrap.innerHTML);
}
</script>