API: yahoo Env.js (YUI Library)

# Yahoo! UI Library

### YAHOO Global 2.8.1

Yahoo! UI Library > yahoo > Env.js (source view)
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    /**
     * YAHOO.env is used to keep track of what is known about the YUI library and
     * the browsing environment
     * @class YAHOO.env
     * @static
     */
    YAHOO.env = YAHOO.env || {

        /**
         * Keeps the version info for all YUI modules that have reported themselves
         * @property modules
         * @type Object[]
         */
        modules: [],

        /**
         * List of functions that should be executed every time a YUI module
         * reports itself.
         * @property listeners
         * @type Function[]
         */
        listeners: []
    };

    /**
     * Returns the version data for the specified module:
     *      <dl>
     *      <dt>name:</dt>      <dd>The name of the module</dd>
     *      <dt>version:</dt>   <dd>The version in use</dd>
     *      <dt>build:</dt>     <dd>The build number in use</dd>
     *      <dt>versions:</dt>  <dd>All versions that were registered</dd>
     *      <dt>builds:</dt>    <dd>All builds that were registered.</dd>
     *      <dt>mainClass:</dt> <dd>An object that was was stamped with the
     *                 current version and build. If
     *                 mainClass.VERSION != version or mainClass.BUILD != build,
     *                 multiple versions of pieces of the library have been
     *                 loaded, potentially causing issues.</dd>
     *       </dl>
     *
     * @method getVersion
     * @static
     * @param {String}  name the name of the module (event, slider, etc)
     * @return {Object} The version info
     */
    YAHOO.env.getVersion = function(name) {
        return YAHOO.env.modules[name] || null;
    };

    /**
     * Do not fork for a browser if it can be avoided.  Use feature detection when
     * you can.  Use the user agent as a last resort.  YAHOO.env.ua stores a version
     * number for the browser engine, 0 otherwise.  This value may or may not map
     * to the version number of the browser using the engine.  The value is
     * presented as a float so that it can easily be used for boolean evaluation
     * as well as for looking for a particular range of versions.  Because of this,
     * some of the granularity of the version info may be lost (e.g., Gecko 1.8.0.9
     * reports 1.8).
     * @class YAHOO.env.ua
     * @static
     */
    YAHOO.env.ua = function() {

            var numberfy = function(s) {
                var c = 0;
                return parseFloat(s.replace(/\./g, function() {
                    return (c++ == 1) ? '' : '.';
                }));
            },

            nav = navigator,

            o = {

            /**
             * Internet Explorer version number or 0.  Example: 6
             * @property ie
             * @type float
             */
            ie: 0,

            /**
             * Opera version number or 0.  Example: 9.2
             * @property opera
             * @type float
             */
            opera: 0,

            /**
             * Gecko engine revision number.  Will evaluate to 1 if Gecko
             * is detected but the revision could not be found. Other browsers
             * will be 0.  Example: 1.8
             * <pre>
             * Firefox 1.0.0.4: 1.7.8   <-- Reports 1.7
             * Firefox 1.5.0.9: 1.8.0.9 <-- Reports 1.8
             * Firefox 2.0.0.3: 1.8.1.3 <-- Reports 1.8
             * Firefox 3 alpha: 1.9a4   <-- Reports 1.9
             * </pre>
             * @property gecko
             * @type float
             */
            gecko: 0,

            /**
             * AppleWebKit version.  KHTML browsers that are not WebKit browsers
             * will evaluate to 1, other browsers 0.  Example: 418.9.1
             * <pre>
             * Safari 1.3.2 (312.6): 312.8.1 <-- Reports 312.8 -- currently the
             *                                   latest available for Mac OSX 10.3.
             * Safari 2.0.2:         416     <-- hasOwnProperty introduced
             * Safari 2.0.4:         418     <-- preventDefault fixed
             * Safari 2.0.4 (419.3): 418.9.1 <-- One version of Safari may run
             *                                   different versions of webkit
             * Safari 2.0.4 (419.3): 419     <-- Tiger installations that have been
             *                                   updated, but not updated
             *                                   to the latest patch.
             * Webkit 212 nightly:   522+    <-- Safari 3.0 precursor (with native SVG
             *                                   and many major issues fixed).
             * 3.x yahoo.com, flickr:422     <-- Safari 3.x hacks the user agent
             *                                   string when hitting yahoo.com and
             *                                   flickr.com.
             * Safari 3.0.4 (523.12):523.12  <-- First Tiger release - automatic update
             *                                   from 2.x via the 10.4.11 OS patch
             * Webkit nightly 1/2008:525+    <-- Supports DOMContentLoaded event.
             *                                   yahoo.com user agent hack removed.
             *
             * </pre>
             * http://developer.apple.com/internet/safari/uamatrix.html
             * @property webkit
             * @type float
             */
            webkit: 0,

            /**
             * The mobile property will be set to a string containing any relevant
             * user agent information when a modern mobile browser is detected.
             * Currently limited to Safari on the iPhone/iPod Touch, Nokia N-series
             * devices with the WebKit-based browser, and Opera Mini.
             * @property mobile
             * @type string
             */
            mobile: null,

            /**
             * Adobe AIR version number or 0.  Only populated if webkit is detected.
             * Example: 1.0
             * @property air
             * @type float
             */
            air: 0,

            /**
             * Google Caja version number or 0.
             * @property caja
             * @type float
             */
            caja: nav.cajaVersion,

            /**
             * Set to true if the page appears to be in SSL
             * @property secure
             * @type boolean
             * @static
             */
            secure: false,

            /**
             * The operating system.  Currently only detecting windows or macintosh
             * @property os
             * @type string
             * @static
             */
            os: null

        },

        ua = navigator && navigator.userAgent,

        loc = window && window.location,

        href = loc && loc.href,

        m;

        o.secure = href && (href.toLowerCase().indexOf("https") === 0);

        if (ua) {

            if ((/windows|win32/i).test(ua)) {
                o.os = 'windows';
            } else if ((/macintosh/i).test(ua)) {
                o.os = 'macintosh';
            }

            // Modern KHTML browsers should qualify as Safari X-Grade
            if ((/KHTML/).test(ua)) {
                o.webkit=1;
            }

            // Modern WebKit browsers are at least X-Grade
            m=ua.match(/AppleWebKit\/([^\s]*)/);
            if (m&&m[1]) {
                o.webkit=numberfy(m[1]);

                // Mobile browser check
                if (/ Mobile\//.test(ua)) {
                    o.mobile = "Apple"; // iPhone or iPod Touch
                } else {
                    m=ua.match(/NokiaN[^\/]*/);
                    if (m) {
                        o.mobile = m[0]; // Nokia N-series, ex: NokiaN95
                    }
                }

                m=ua.match(/AdobeAIR\/([^\s]*)/);
                if (m) {
                    o.air = m[0]; // Adobe AIR 1.0 or better
                }

            }

            if (!o.webkit) { // not webkit
                // @todo check Opera/8.01 (J2ME/MIDP; Opera Mini/2.0.4509/1316; fi; U; ssr)
                m=ua.match(/Opera[\s\/]([^\s]*)/);
                if (m&&m[1]) {
                    o.opera=numberfy(m[1]);
                    m=ua.match(/Opera Mini[^;]*/);
                    if (m) {
                        o.mobile = m[0]; // ex: Opera Mini/2.0.4509/1316
                    }
                } else { // not opera or webkit
                    m=ua.match(/MSIE\s([^;]*)/);
                    if (m&&m[1]) {
                        o.ie=numberfy(m[1]);
                    } else { // not opera, webkit, or ie
                        m=ua.match(/Gecko\/([^\s]*)/);
                        if (m) {
                            o.gecko=1; // Gecko detected, look for revision
                            m=ua.match(/rv:([^\s\)]*)/);
                            if (m&&m[1]) {
                                o.gecko=numberfy(m[1]);
                            }
                        }
                    }
                }
            }
        }

        return o;
    }();

    /*
     * Initializes the global by creating the default namespaces and applying
     * any new configuration information that is detected.  This is the setup
     * for env.
     * @method init
     * @static
     * @private
     */
    (function() {
        YAHOO.namespace("util", "widget", "example");
        /*global YAHOO_config*/
        if ("undefined" !== typeof YAHOO_config) {
            var l=YAHOO_config.listener, ls=YAHOO.env.listeners,unique=true, i;
            if (l) {
                // if YAHOO is loaded multiple times we need to check to see if
                // this is a new config object.  If it is, add the new component
                // load listener to the stack
                for (i=0; i<ls.length; i++) {
                    if (ls[i] == l) {
                        unique = false;
                        break;
                    }
                }

                if (unique) {
                    ls.push(l);
                }
            }
        }
    })();

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