How to filter html, js, and css code in Asp.net

Reference content is as follows: # Region // filter html, js, and css code /// <Summary> /// Filter html, js, and css code /// </Summary> /// <Param name = "html"> parameter input </param> /// <Returns> </returns> Public static string CheckStr (string html) { System. text. regularExpressions. regex regex1 = new System. text. regularExpressions. regex (@ "<script [\ s \ S] + </script *>", System. text. regularExpressions. regexOptions. ignoreCase ); System. text. regularExpressions. regex regex2 = new System. text. regularExpressions. regex (@ "href * = * [\ s \ S] * script *:", System. text. regularExpressions. regexOptions. ignoreCase ); System. text. regularExpressions. regex regex3 = new System. text. regularExpressions. regex (@ "no [\ s \ S] * =", System. text. regularExpressions. regexOptions. ignoreCase ); System. text. regularExpressions. regex regex4 = new System. text. regularExpressions. regex (@ "<iframe [\ s \ S] + </iframe *>", System. text. regularExpressions. regexOptions. ignoreCase ); System. text. regularExpressions. regex regex5 = new System. text. regularExpressions. regex (@ "<frameset [\ s \ S] + </frameset *>", System. text. regularExpressions. regexOptions. ignoreCase ); System. text. regularExpressions. regex regex6 = new System. text. regularExpressions. regex (@ "\ ] + \>", 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, ""); // filter <script> </script> tags Html = regex2.Replace (html, ""); // filter href = javascript: (<A>) attributes Html = regex3.Replace (html, "_ disibledevent ="); // filter events of other controls. Html = regex4.Replace (html, ""); // filter iframe Html = regex5.Replace (html, ""); // filter frameset Html = regex6.Replace (html, ""); // filter frameset Html = regex7.Replace (html, ""); // filter frameset Html = regex8.Replace (html, ""); // filter frameset Html = regex9.Replace (html ,""); Html = html. Replace ("",""); Html = html. Replace ("</strong> ",""); Html = html. Replace ("<strong> ",""); Return html; } # Endregion # Region // filter p/p code /// <Summary> /// Filter p/p code /// </Summary> /// <Param name = "html"> parameter input </param> /// <Returns> </returns> Public static string InputStr (string html) { Html = html. Replace (@ "\ ] + \> ",""); Html = html. Replace (@ "<p> ",""); Html = html. Replace (@ "</p> ",""); Return html; } # Endregion /// <Summary> /// Capture a string /// </Summary> /// <Param name = "str"> </param> /// <Param name = "length"> </param> /// <Returns> </returns> Protected string GetLength (string str, int length) { String strR = str; If (str. Length> length) { StrR = str. Substring (0, length) + "..."; } Return strR; }