Question

Yeah, I know that feature detection is preferable.

I’ve got a case in my codebase where we are using $.browser.msie and $.browser.version to decide whether to render some CSS or not. The developer who wrote the code is no longer with us, and I don’t fully understand exactly what kind of feature detection I should write here instead.

As a quick fix, what’s the shortest way to implement $.browser.msie and $.browser.version?

Answer 1

I’ll just copy the code from jQuery 1.8.3.

// 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;
})();