js在网页中判断横屏竖屏

window.onload = function () {
after_ready_change();
}
//判断手机横竖屏状态：
function hengshuping(){
if(window.orientation==180||window.orientation==0){
after_ready_change();
}
if(window.orientation==90||window.orientation==-90){
after_ready_change();
}
}
window.addEventListener("onorientationchange" in window ? "orientationchange" : "resize", hengshuping, false);