方法一：

/// <summary>

  /// 去除HTML标记

  /// </summary>

  /// <param name="NoHTML">包括HTML的源码 </param>

  /// <returns>已经去除后的文字</returns>

  public static string NoHTML(string Htmlstring)

  {

   //删除脚本

   Htmlstring = Regex.Replace(Htmlstring,@"<script[^>]*?>.*?</script>","",RegexOptions.IgnoreCase);

   //删除HTML

   Htmlstring = Regex.Replace(Htmlstring,@"<(.[^>]*)>","",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"([\r\n])[\s]+","",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"-->","",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"<!--.*","",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(quot|#34);","\"",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(amp|#38);","&",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(lt|#60);","<",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(gt|#62);",">",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(nbsp|#160);"," ",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(iexcl|#161);","\xa1",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(cent|#162);","\xa2",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(pound|#163);","\xa3",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring,@"&(copy|#169);","\xa9",RegexOptions.IgnoreCase);

   Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);","",RegexOptions.IgnoreCase);

   Htmlstring.Replace("<","");

   Htmlstring.Replace(">","");

   Htmlstring.Replace("\r\n","");

   //Htmlstring=HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();

   return Htmlstring;

  }

方法二：

var str = "<span style="display:none;" mce_style="display:none;">This is test</span><img src=http://www.mamicode.com/‘‘>
";     

str = str.replace(/<[^>].*?>/g,"");     

alert(str);  

js 去掉html标签