Sys.Browser.WebKit = {}; //Safari 3 is considered WebKit
if (navigator.userAgent.indexOf('WebKit/') > -1) {
    Sys.Browser.agent = Sys.Browser.WebKit;
    Sys.Browser.version = parseFloat(navigator.userAgent.match(/WebKit\/(\d+(\.\d+)?)/)[1]);
    Sys.Browser.name = 'WebKit';
}

//http://blog.lavablast.com/post/2008/10/Gotcha-WebKit-(Safari-3-and-Google-Chrome)-Bug-with-ASPNET-AJAX.aspx
//http://blog.turlov.com/2009/01/aspnet-ajax-compatibility-patch-for.html
//http://forums.asp.net/p/1252014/2898429.aspx