通用手机端样式：
media all and (orientation : portrait) {
/*竖屏*/
}
media all and (orientation : landscape) {
/*横屏*/
}
指定手机端高度样式：
media screen and (max-width: 750px)
media screen and (min-width: 720px) and (max-width: 960px) {//720 <= xxx =768的设备
JS制作手机端自适应缩放显示
示例一：
[removed]
var _width = parseInt(window.screen.width);
var scale = _width/640;
var ua = navigator.userAgent.toLowerCase();
var result = /android (\d+\.\d+)/.exec(ua);
if (result){
var version = parseFloat(result[1]);
if(version>
