很多站点都是用了静态文件分离。我推荐一种处理静态文件分离的方式。

BundleExtensions.cs

 public static class BundleExtensions    {        public static string Version = "1.0.0";        public static string ScriptsPath = "Cdn";        public static Bundle Production(this Bundle bundle, string cdn, string root, string minified,            string full = "")        {            var transform = new ScriptsBundleTransform()            {                Version = Version,                ScriptsPath = System.IO.Path.Combine("~/", ScriptsPath, root),                Minified = minified,                Full = full            };            bundle.Transforms.Add(transform);            bundle.CdnPath = cdn + "/" + root + "/" + string.Format("{0}?{1}", minified, Version);            return bundle;        }    }

ScriptsBundleTransform.cs

public class ScriptsBundleTransform : IBundleTransform    {        public string ScriptsPath { get; set; }        public string Version { get; set; }        public string Minified { get; set; }        public string Full { get; set; }        public ScriptsBundleTransform()        {        }        public ScriptsBundleTransform(string path, string version, string minified, string full)        {            ScriptsPath = path;            Version = version;            Minified = minified;            Full = full;        }        public void Process(BundleContext context, BundleResponse response)        {            string scriptsRoot = context.HttpContext.Server.MapPath(ScriptsPath);            if (!Directory.Exists(scriptsRoot))                Directory.CreateDirectory(scriptsRoot);            //  if minified file name specified...            if (!string.IsNullOrEmpty(Minified))            {                using (TextWriter writer = File.CreateText(Path.Combine(scriptsRoot, Minified)))                {                    writer.Write(response.Content);                }            }            //  if full file name specified...            if (!string.IsNullOrEmpty(Full))            {                using (Stream writer = File.OpenWrite(Path.Combine(scriptsRoot, Full)))                {                    foreach (var file in response.Files)                    {                        file.VirtualFile.Open().CopyTo(writer);                    }                }            }        }    }

BundleConfig.cs

        public static void RegisterBundles(BundleCollection bundles)        {            bundles.UseCdn = true;            BundleTable.EnableOptimizations = true;            //制定压缩后的资源存储路径            BundleExtensions.ScriptsPath = "Resource";            //制定请求时代的后缀，为了刷新掉客户端的缓存            BundleExtensions.Version = "00001";            //CDN站点地址            const string ajaxCdnPath = "http://localhost/Cdn";            bundles.Add(new ScriptBundle("~/bundles/bootstrap")                .IncludeFallback("$.fn.affix",                    "~/Resource/Scripts/common/transition.js",                    "~/Resource/Scripts/common/button.js",                    "~/Resource/Scripts/common/affix.js",                    "~/Resource/Scripts/common/tab.js",                    "~/Resource/Scripts/common/collapse.js",                    "~/Resource/Scripts/common/tooltip.js",                    "~/Resource/Scripts/common/respond.js")                .Production(ajaxCdnPath, "Scripts", "bootstrap.mincdn.js", "bootstrap.src.js"));            bundles.Add(new ScriptBundle("~/Content/bootstrap")                .Include("~/Resource/Content/bootstrap.css")                .Include("~/Resource/Content/common/button.css")                .Include("~/Resource/Content/common/bootstrap-theme.css")                .Production(ajaxCdnPath, "Content", "bootstrap.mincdn.css", "bootstrap.src.css"));        }

这样的话就能生成 CDN 站点下的JS文件引用了

<script src="http://localhost/Cdn/Scripts/bootstrap.mincdn.js?00001"></script>

对了这里漏掉了一个地方，

http://localhost/Cdn站点需要你在IIS中指定到你站点的Resource下，不然访问不到你的JS文件。

但是如果CDN站点挂掉了怎么办，咱们继续：

SctiptsBundleExtensions.cs

    public static class SctiptsBundleExtensions    {        public static ScriptBundle IncludeFallback(this ScriptBundle bundle, string cdnFallbackExpression,            string virtualPath, params IItemTransform[] transforms)        {            bundle.CdnFallbackExpression = cdnFallbackExpression;            bundle.Include(virtualPath, transforms);            return bundle;        }        public static ScriptBundle IncludeFallback(this ScriptBundle bundle, string cdnFallbackExpression,          params string[] virtualPaths)        {            bundle.CdnFallbackExpression = cdnFallbackExpression;            bundle.Include(virtualPaths);            return bundle;        }    }

        bundles.Add(new ScriptBundle("~/bundles/jquery")                .IncludeFallback("window.jQuery", "~/Resource/Scripts/common/jquery-{version}.js")                .Production(ajaxCdnPath, "Scripts", "jquery.mincdn.js", "jquery.src.js"));

这样会生成如下的JS应用：

<script src="http://localhost/Cdn/Scripts/jquery.mincdn.js?00001"></script><script>(window.jQuery)||document.write('<script src="/dome/bundles/jquery"><//script>');</script>

这样的话当CDN站点挂掉了还是能够访问到JS文件的。

接下来CSS怎么处理呢：

StyleBundleExtensions.cs

 public static class StyleBundleExtensions    {        /// <summary>        /// Include a stylesheet to fallback to when external CdnPath does not load.        /// </summary>        /// <param name="bundle"></param>        /// <param name="fallback">Virtual path to fallback stylesheet</param>        /// <param name="className">Stylesheet class name applied to test DOM element</param>        /// <param name="ruleName">Rule name to test when the class is applied ie. width</param>        /// <param name="ruleValue">Value to test when the class is applied ie. 1px</param>        /// <returns></returns>        public static StyleBundle IncludeFallback(this StyleBundle bundle, string fallback,            string className = null, string ruleName = null, string ruleValue = null)        {            if (String.IsNullOrEmpty(bundle.CdnPath))            {                throw new Exception("CdnPath must be provided when specifying a fallback");            }            if (VirtualPathUtility.IsAppRelative(bundle.CdnPath))            {                bundle.CdnFallbackExpress(fallback);            }            else if (new[] { className, ruleName, ruleValue }.Any(String.IsNullOrEmpty))            {                throw new Exception(                    "IncludeFallback for cross-domain CdnPath must provide values for parameters [className, ruleName, ruleValue].");            }            else            {                bundle.CdnFallbackExpress(fallback, className, ruleName, ruleValue);            }            return bundle;        }        private static StyleBundle CdnFallbackExpress(this StyleBundle bundle, string fallback,            string className = null, string ruleName = null, string ruleValue = null)        {            bundle.Include(fallback);            fallback = VirtualPathUtility.ToAbsolute(fallback);            bundle.CdnFallbackExpression = String.IsNullOrEmpty(className) ?                String.Format(@"function() {{                var len = document.styleSheets.length;                for (var i = 0; i < len; i++) {{                    var sheet = document.styleSheets[i];                    if (sheet.href.indexOf('{0}') !== -1) {{                        var rules = sheet.rules || sheet.cssRules;                        if (rules.length <= 0) {{                            document.write('<link href=""{1}"" rel=""stylesheet"" type=""text/css"" />');                        }}                    }}                }}                return true;                }}()", bundle.CdnPath, fallback) :                String.Format(@"function() {{                var loadFallback,                    len = document.styleSheets.length;                for (var i = 0; i < len; i++) {{                    var sheet = document.styleSheets[i];                    if (sheet.href.indexOf('{0}') !== -1) {{                        var meta = document.createElement('meta');                        meta.className = '{2}';                        document.head.appendChild(meta);                        var value = window.getComputedStyle(meta).getPropertyValue('{3}');                        document.head.removeChild(meta);                        if (value !== '{4}') {{                            document.write('<link href=""{1}"" rel=""stylesheet"" type=""text/css"" />');                        }}                    }}                }}                return true;            }}()", bundle.CdnPath, fallback, className, ruleName, ruleValue);            return bundle;        }    }

好吧后面的大家自己摸索吧：）上班了
很多代码是网上抄袭的，东拼西凑。