Cambio de viewport según la orientación

scripts.js

/** Basado en: https://stackoverflow.com/questions/15040408/achieving-min-width-with-viewport-meta-tag */

document.addEventListener('DOMContentLoaded', function () {
    trasweb.orientationchange();
});
trasweb.orientationchange = function (force_orientation) {

    var vp = document.getElementById('viewport');
    var orientation = window.orientation;
    var is_desktop = document.body.classList.contains('desktop');
    var max = trasweb.getMax();

    if (is_desktop) {
        /** Tablet giradas */
        if (180 === orientation) {
            var ratio = parseInt(max[0], 10) / 1600;
            vp.setAttribute('content', 'width=1600, initial-scale=' + ratio + ', maximum-scale=' + ratio + ', user-scalable=yes');
            document.body.classList.add('tablet-landscape');
        } else if ((-90 === orientation || 90 === orientation) && max[0] <= 1024) {
            var ratio = parseInt(max[0], 10) / 1024;
            vp.setAttribute('content', 'width=1024, initial-scale=' + ratio + ', maximum-scale=' + ratio + ', user-scalable=yes');
            document.body.classList.add('tablet-portrait');

        }

        return;
    }

    if (-90 === orientation || 90 === orientation) {
        vp.setAttribute('content', 'width=640, initial-scale=1');
        document.body.classList.add('landscape');
    } else {
        vp.setAttribute('content', 'width=360, initial-scale=1.0, maximum-scale=1.0, user-scalable=no');
        document.body.classList.add('portrait');
    }
};

window.addEventListener('orientationchange', function () {
    window.location.reload(true);
});