判断设备是否横屏

css3/* For portrait, we want the tool bar on top */
//横屏
@media screen and (orientation: portrait) {
  #toolbar {
    width: 100%;
  }
}

/* For landscape, we want the tool bar stick on the left */
//竖屏
@media screen and (orientation: landscape) {
  #toolbar {
    position: fixed;
    width: 2.65em;
    height: 100%;
  }

  p {
    margin-left: 2em;
  }

  li + li {
    margin-top: .5em;
  }
}

js

　判断是横屏还是竖屏的方法:　　function orient() {if (window.orientation == 90 || window.orientation == -90) {//ipad、iphone竖屏；Andriod横屏$("body").attr("class", "landscape");orientation = ‘landscape‘;return false;}else if (window.orientation == 0 || window.orientation == 180) {//ipad、iphone横屏；Andriod竖屏$("body").attr("class", "portrait");orientation = ‘portrait‘;return false;}}//页面加载时调用$(function(){orient();});//用户变化屏幕方向时调用$(window).bind( ‘orientationchange‘, function(e){orient();});