orientation-body-class.js

// Add orientation body class.
window.addEventListener("DOMContentLoaded", function(){
    var cls = ["landscape", "portrait"];
    var clsRe = new RegExp("(" + cls.join("|") + ")");
    var event = "onorientationchange" in window ? "orientationchange" : "resize";
    document.body.className += " " + getClass();
    
    window.addEventListener(event, function(){
        var className = document.body.className;
        document.body.className = className ? className.replace(clsRe, getClass()) : getClass();
    }, true);   
    
    function getClass(){
        return cls[window.orientation % 180 ? 0 : 1];
    }    
}, true);