什么是jquery.browser的快速,纯粹的javascript替换(在jquery 1.9中删除)？

// Limit scope pollution from any deprecated API
(function() {

var matched,browser;

// Use of jQuery.browser is frowned upon.
// More details: http://api.jquery.com/jQuery.browser
// jQuery.uaMatch maintained for BACk-compat
jQuery.uaMatch = function( ua ) {
    ua = ua.toLowerCase();

    var match = /(chromE)[ \/]([\w.]+)/.exec( ua ) ||
        /(webkit)[ \/]([\w.]+)/.exec( ua ) ||
        /(opera)(?:.*version|)[ \/]([\w.]+)/.exec( ua ) ||
        /(msiE) ([\w.]+)/.exec( ua ) ||
        ua.indexOf("compatible") < 0 && /(mozilla)(?:.*? rv:([\w.]+)|)/.exec( ua ) ||
        [];

    return {
        browser: match[ 1 ] || "",version: match[ 2 ] || "0"
    };
};

matched = jQuery.uaMatch( navigator.userAgent );
browser = {};

if ( matched.browser ) {
    browser[ matched.browser ] = true;
    browser.version = matched.version;
}

// Chrome is Webkit,but Webkit is also Safari.
if ( browser.chrome ) {
    browser.webkit = true;
} else if ( browser.webkit ) {
    browser.safari = true;
}

jQuery.browser = browser;
})();