Platform CSS class on HTML tag

platform.js

/**
 * Platform CSS class on HTML tag inspired by https://github.com/driftyco/ionic/blob/67ef9ebde21ac64e1f9e3db43b16c2db7ed2256d/js/utils/platform.js
 */
(function(w, el) {
    var platformName,
        IOS = 'ios',
        ANDROID = 'android',
        WINDOWS_PHONE = 'windowsphone',
        EDGE = 'edge',
        CROSSWALK = 'crosswalk';

    // Fallback
    if (!el) {
        el = w.document.getElementsByTagName('html')[0];
    }

    this.setPlatform = function (n) {
        if (n.indexOf('Edge') > -1) {
            platformName = EDGE;
        } else if (n.indexOf('Windows Phone') > -1) {
            platformName = WINDOWS_PHONE;
        } else if (n.indexOf('Android') > 0) {
            platformName = ANDROID;
        } else if (/iPhone|iPad|iPod/.test(n)) {
            platformName = IOS;
        } else {
            platformName = w.navigator.platform && w.navigator.platform.toLowerCase().split(' ')[0] || '';
        }
    }

    this.setPlatform(window.navigator.userAgent);

    if (platformName) {
        el.className += ' platform-' + platformName;
    }

}(window, typeof platformTagTarget !== 'undefined' ? platformTagTarget : null));