/**
 * 獲取HTTP請求的Referer
 * @ishost 布爾類型 Referer為空時是否返回Host（網站首頁地址）
 */
function get_http_referer(ishost) {
    if (ishost === undefined) { ishost = true; }
    if (document.referrer) {
        return document.referrer;
    } else {
        if (ishost) {
            return window.location.protocol + "http://" + window.location.host;
        } else {
            return "";
        }
    }
}

/// <summary>
/// 獲取HTTP請求的Referer
/// </summary>
/// <param name="ishost">Referer為空時是否返回Host（網站首頁地址）</param>
/// <returns>string</returns>
public string GetReferer(bool ishost)
{
    if ( Request.UrlReferrer != null)
    {
        return  Request.UrlReferrer.ToString();
    }
    else
    {
        if (ishost)
        {
            return Request.Url.Scheme + "://" + Request.Url.Authority;
        }
        else
        {
            return "";
        }
    }
}

Request.ApplicationPath /
Request.PhysicalPath D:/Projects/Solution/web/News/Press/Content.aspx
System.IO.Path.GetDirectoryName(Request.PhysicalPath) D:/Projects/Solution/web/News/Press
Request.PhysicalApplicationPath D:/Projects/Solution/web/
System.IO.Path.GetFileName(Request.PhysicalPath) Content.aspx
Request.CurrentExecutionFilePath /News/Press/Content.aspx
Request.FilePath /News/Press/Content.aspx
Request.Path /News/Press/Content.aspx/123
Request.RawUrl /News/Press/Content.aspx/123?id=1
Request.Url.AbsolutePath /News/Press/Content.aspx/123
Request.Url.AbsoluteUri http://localhost:1897/News/Press/Content.aspx/123?id=1
Request.Url.Scheme http
Request.Url.Host localhost
Request.Url.Port 1897
Request.Url.Authority localhost:1897
Request.Url.LocalPath /News/Press/Content.aspx/123
Request.PathInfo /123
Request.Url.PathAndQuery /News/Press/Content.aspx/123?id=1
Request.Url.Query ?id=1
Request.Url.Fragment 
Request.Url.Segments /
News/
Press/
Content.aspx/
123