/// <summary>
/// 给CSS文件或JS文件指定版本号
/// </summary>
/// <param name="helper"></param>
/// <param name="url">CSS或JS路径</param>
/// <returns></returns>
public static string GetCssJsUrl(this HtmlHelper helper, string url)
{
string version = ConfigurationManager.AppSettings["JsVersion"];
version = version == null ? "1.0" : version;
var rootPath = DocumentPath.TrimEnd('/');
url = rootPath + url;
return(url += "?v=" + version);
}