移动端判断是否处于横屏还是竖屏状态

style>
    @media screen and (orientation:portrait) {
        /* portrait-specific styles */
    }
    /* landscape */
    @media screen and (orientation:landscape) {
        /* landscape-specific styles */
    }
</style>

<script type="text/javascript">
    var mql = window.matchMedia("(orientation: portrait)");
    if(mql.matches) {
        alert("竖屏");
    } else {
        alert("横屏");
    }
    // 添加一个媒体查询改变监听者
    mql.addListener(function(m) {
        if(m.matches) {
            alert("竖屏");
        }
        else {
            alert("横屏");
        }
    });
</script>