js如何判断手机横屏还是竖屏的方法

<link rel="stylesheet" media="all and (orientation:portrait)" href="portrait.css" rel="external nofollow" > //引用竖屏的CSS　
<link rel="stylesheet" media="all and (orientation:landscape)" href="landscape.css" rel="external nofollow" > //引用横屏的CSS

@media (orientation: portrait ){ //竖屏CSS }
@media ( orientation: landscape ){ //横屏CSS }

window.addEventListener("onorientationchange" in window ? "orientationchange" : "resize", function() {  if (window.orientation === 180 || window.orientation === 0) { 
   alert('竖屏状态！');
  } 
  if (window.orientation === 90 || window.orientation === -90 ){ 
   alert('横屏状态！');
  } 
 }, false);

function orient() {        //alert('gete');
        if (window.orientation == 0 || window.orientation == 180) {
            $("body").attr("class", "portrait");
            orientation = 'portrait';            return false;
        }        else if (window.orientation == 90 || window.orientation == -90) {
            $("body").attr("class", "landscape");
            orientation = 'landscape';   
            return false;
        }
    }
    $(function(){
        orient();
    });
   
    $(window).bind( 'orientationchange', function(e){
        orient();
    });
ipad： 90 或 -90 横屏
ipad： 0 或180 竖屏
Andriod：0 或180 横屏
Andriod： 90 或 -90 竖屏
转载于：https://www.jianshu.com/p/43b991eba5e5

//转载地址：https://www.cnblogs.com/hanguozhi/p/7405840.html 
(function rotate(){   var orientation=window.orientation;   var pd = null;
   function createPd(){       if(document.getElementById('preventTran') === null){            var imgData = 'data:image/png;base64,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';
            pd = document.createElement('div');
            pd.setAttribute('id','preventTran');
            pd.style.position = 'fixed';
            pd.style.left = '0';
            pd.style.top = '0';
            pd.style.width = '100%';
            pd.style.height = '100%';
            pd.style.overflow = 'hidden';
            pd.style.backgroundColor = '#2e2e2e';
            pd.style.textAlign = 'center';
            pd.style.zIndex = '99999';
            document.getElementsByTagName('body')[0].appendChild(pd);            var img = document.createElement('img');
            img.src = imgData;
            pd.appendChild(img);
            img.style.margin = '60px auto 30px'
            var br = document.createElement('br');            var p = document.createElement('p');
            p.style.width = '100%';
            p.style.height = 'auto';
            p.style.fontSize = '22px';
            p.style.color = '#626262';
            p.style.lineHeight = '34px';
            p.style.textAlign = 'center';
            p.innerHTML = '为了您的良好体验';
            p.appendChild(br);
            p.innerHTML += '请将手机/平板竖屏操作';
            pd.appendChild(p);
        }
   }   if(orientation==90||orientation==-90){        if(pd == null && document.getElementById('preventTran') === null) createPd();
        document.getElementById('preventTran').style.display = 'block';
   }
   window.onorientationchange=function(){      if(pd == null && document.getElementById('preventTran') == null) createPd();
      document.getElementById('preventTran').style.display='none';
      rotate();
   };
})();