How to detect browser version with jquery

var detectBrowserVersion = function() {
    var userAgent = navigator.userAgent.toLowerCase();
    $.browser.chrome = /chrome/.test(navigator.userAgent.toLowerCase());
    var version = 0;

    // Is this a version of IE?
    if($.browser.msie){
        userAgent = $.browser.version;
        userAgent = userAgent.substring(0,userAgent.indexOf('.'));   
        version = userAgent;
    }

    // Is this a version of Chrome?
    if($.browser.chrome){
        userAgent = userAgent.substring(userAgent.indexOf('chrome/') +7);
        userAgent = userAgent.substring(0,userAgent.indexOf('.'));   
        version = userAgent;
        // If it is chrome then jQuery thinks it's safari so we have to tell it it isn't
        $.browser.safari = false;
    }

    // Is this a version of Safari?
    if($.browser.safari){
        userAgent = userAgent.substring(userAgent.indexOf('safari/') +7);   
        userAgent = userAgent.substring(0,userAgent.indexOf('.'));
        version = userAgent;   
    }

    // Is this a version of Mozilla?
    if($.browser.mozilla){
        //Is it Firefox?
        if(navigator.userAgent.toLowerCase().indexOf('firefox') != -1){
            userAgent = userAgent.substring(userAgent.indexOf('firefox/') +8);
            userAgent = userAgent.substring(0,userAgent.indexOf('.'));
            version = userAgent;
        }
        // If not then it must be another Mozilla
        else{
        }
    }

    // Is this a version of Opera?
    if($.browser.opera){
        userAgent = userAgent.substring(userAgent.indexOf('version/') +8);
        userAgent = userAgent.substring(0,userAgent.indexOf('.'));
        version = userAgent;
    }
    //return version;
}

How to use:

detectBrowserVersion();

    if ($.browser.chrome || $.browser.safari) {
        //navigation detection in Chrome browser
        $(document).keydown(function(e){
            dokeypress(e);
        });
   
    } else {
        //detect keypress
        $(document).keypress(function(e){
            dokeypress(e);
        });
    }