private string FilterHTML(string html)
        {
            System.Text.RegularExpressions.Regex regex1 =
                  new System.Text.RegularExpressions.Regex(@"<script[sS]+</script *>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex2 =
                  new System.Text.RegularExpressions.Regex(@" href *= *[sS]*script *:",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex3 =
                  new System.Text.RegularExpressions.Regex(@" no[sS]*=",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex4 =
                  new System.Text.RegularExpressions.Regex(@"<iframe[sS]+</iframe *>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex5 =
                  new System.Text.RegularExpressions.Regex(@"<frameset[sS]+</frameset *>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex6 =
                  new System.Text.RegularExpressions.Regex(@"<img[^>]+>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex7 =
                  new System.Text.RegularExpressions.Regex(@"</p>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex8 =
                  new System.Text.RegularExpressions.Regex(@"<p>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            System.Text.RegularExpressions.Regex regex9 =
                  new System.Text.RegularExpressions.Regex(@"<[^>]*>",
                  System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            html = regex1.Replace(html, ""); //过滤<script></script>标记 
            html = regex2.Replace(html, ""); //过滤href=javascript: (<A>) 属性 
            html = regex3.Replace(html, " _disibledevent="); //过滤其它控件的on...事件 
            html = regex4.Replace(html, ""); //过滤iframe 
            html = regex5.Replace(html, ""); //过滤frameset 
            html = regex6.Replace(html, ""); //过滤frameset 
            html = regex7.Replace(html, ""); //过滤frameset 
            html = regex8.Replace(html, ""); //过滤frameset 
            html = regex9.Replace(html, "");
            //html = html.Replace(" ", "");
            html = html.Replace("</strong>", "");
            html = html.Replace("<strong>", "");
            html = Regex.Replace(html, "[\f\n\r\t\v]", "");  //过滤回车换行制表符
            return html;
        }