横竖屏切换检测代码

test_screen_landscape_or_portrait.js

(function() {
    var supportOrientation = (typeof window.orientation === 'number' &&
        typeof window.onorientationchange === 'object');

    var init = function() {
        var htmlNode = document.body.parentNode,
            orientation;
        var updateOrientation = function() {
            if (supportOrientation) {
                orientation = window.orientation;
                switch (orientation) {
                    case 90:
                    case -90:
                        orientation = 'landscape';
                        break;
                    default:
                        orientation = 'portrait';
                        break;
                }
            } else {
                orientation = (window.innerWidth > window.innerHeight) ? 'landscape' : 'portrait';
            }
            htmlNode.setAttribute('class', orientation);
        };

        if (supportOrientation) {
            window.addEventListener('orientationchange', updateOrientation, false);
        } else {
            //监听resize事件
            window.addEventListener('resize', updateOrientation, false);
        }

        updateOrientation();
    };

    window.addEventListener('DOMContentLoaded', init, false);
})();