.net阻止XSS攻击方法

      public static string FilterXSS(this string html)
        {
            if (string.IsNullOrEmpty(html)) return string.Empty;

            // CR(0a) ，LF(0b) ，TAB(9) 除外，过滤掉所有的不打印出来字符.    
            // 目的防止这样形式的入侵 ＜java\0script＞   
            // 注意：\n, \r,  \t 可能需要单独处理，因为可能会要用到   
            string ret = System.Text.RegularExpressions.Regex.Replace(
                html, "([\x00-\x08][\x0b-\x0c][\x0e-\x20])", string.Empty);

            //替换所有可能的16进制构建的恶意代码   
            //<IMG SRC=&#X40&#X61&#X76&#X61&#X73&#X63&#X72&#X69&#X70&#X74&#X3A&#X61&_#X6C&#X65&#X72&#X74&#X28&#X27&#X58&#X53&#X53&#X27&#X29>  
            string chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()~`;:?+/={}[]-_|'\"\\";
            for (int i = 0; i < chars.Length; i++)
            {
                ret = System.Text.RegularExpressions.Regex.Replace(ret, string.Concat("(&#[x|X]0{0,}", Convert.ToString((int)chars[i], 16).ToLower(), ";?)"),
                    chars[i].ToString(), System.Text.RegularExpressions.RegexOptions.IgnoreCase);
            }

            //过滤\t, \n, \r构建的恶意代码  
            string[] keywords = {"javascript","alert", "vbscript", "expression", "applet", "meta", "xml", "blink", "link", "style", "script", "embed", "object", "iframe", "frame", "frameset", "ilayer", "layer", "bgsound", "title", "base"
        ,"onabort", "onactivate", "onafterprint", "onafterupdate", "onbeforeactivate", "onbeforecopy", "onbeforecut", "onbeforedeactivate", "onbeforeeditfocus", "onbeforepaste", "onbeforeprint", "onbeforeunload", "onbeforeupdate", "onblur", "onbounce", "oncellchange", "onchange", "onclick", "oncontextmenu", "oncontrolselect", "oncopy", "oncut", "ondataavailable", "ondatasetchanged", "ondatasetcomplete", "ondblclick", "ondeactivate", "ondrag", "ondragend", "ondragenter", "ondragleave", "ondragover", "ondragstart", "ondrop", "onerror", "onerrorupdate", "onfilterchange", "onfinish", "onfocus", "onfocusin", "onfocusout", "onhelp", "onkeydown", "onkeypress", "onkeyup", "onlayoutcomplete", "onload", "onlosecapture", "onmousedown", "onmouseenter", "onmouseleave", "onmousemove", "onmouseout", "onmouseover", "onmouseup", "onmousewheel", "onmove", "onmoveend", "onmovestart", "onpaste", "onpropertychange", "onreadystatechange", "onreset", "onresize", "onresizeend", "onresizestart", "onrowenter", "onrowexit", "onrowsdelete", "onrowsinserted", "onscroll", "onselect", "onselectionchange", "onselectstart", "onstart", "onstop", "onsubmit", "document","cookie","onunload"};
           

            bool found = true;
            while (found)
            {
                var retBefore = ret;
                for (int i = 0; i < keywords.Length; i++)
                {
                    string pattern = "/";
                    for (int j = 0; j < keywords[i].Length; j++)
                    {
                        if (j > 0)
                            pattern = string.Concat(pattern, '(', "(&#[x|X]0{0,8}([9][a][b]);?)?", "|(&#0{0,8}([9][10][13]);?)?",
                                ")?");
                        pattern = string.Concat(pattern, keywords[i][j]);
                    }
                    string replacement = string.Concat(keywords[i].Substring(0, 2), "＜x＞", keywords[i].Substring(2));
                    //ret = System.Text.RegularExpressions.Regex.Replace(ret, pattern, replacement, System.Text.RegularExpressions.RegexOptions.IgnoreCase);
                    ret = ret.Replace(keywords[i], "");
                    if (ret == retBefore)
                        found = false;
                }

            }

            return ret;
        }