Asp.net UDFs filter HTML tags with only line breaks and spaces

I found a method to filter HTML tags from the internet. I don't know who is the original one. Most of them are the same. I copied the method and the code is as follows:

The code is as follows:

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/// <Summary> /// Remove HTML tags /// </Summary> /// <Param name = "NoHTML"> including the source code of HTML </param> /// <Returns> Removed text </returns> Public static string NoHTML (string Htmlstring) { // Delete the script Htmlstring = Regex. Replace (Htmlstring, @ "<script [^>] *?>. *? </Script> ","", RegexOptions. IgnoreCase ); // Delete HTML Htmlstring = Regex. Replace (Htmlstring, @ "<(. [^>] *)> ","", RegexOptions. IgnoreCase ); Htmlstring = Regex. Replace (Htmlstring, @ "([rn]) [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 ("rn ",""); Htmlstring = HttpContext. Current. Server. HtmlEncode (Htmlstring). Trim (); Return Htmlstring; }

The above code is directly copied from the internet. This can indeed filter out all HTML tags, but this is not what I want and it is too clean, if I use the textarea input box, I want to keep spaces and line breaks.

Then I changed this method myself. The newline of textarea is n, so I have to replace these tags with <br>. In this way, when reading the page from the database, the line feed is correct, and the space is replaced with the HTML space character.

The code is as follows:

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/// <Summary> /// Remove the HTML tag (retain the br and rn) (this method was changed from "blog garden" to "three-volume Tianshu) /// </Summary> /// <Param name = "NoHTML"> including the source code of HTML </param> /// <Returns> Removed text </returns> Public static string NewNoHTML (string Htmlstring) { // Htmlstring. replace ("rn", "% r % n "). replace ("<br>", "% br % "). replace ("<br/>", "% br & % "). replace ("n", "% n "); // Delete the script Htmlstring = Regex. Replace (Htmlstring, @ "<script [^>] *?>. *? </Script> ","", RegexOptions. IgnoreCase ); // Delete HTML Htmlstring = Regex. Replace (Htmlstring, @ "<(. [^>] *)> ","", 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 ("rn ",""); Htmlstring = HttpContext. Current. Server. HtmlEncode (Htmlstring ); Htmlstring = Regex. Replace (Htmlstring, @ "(rn)", "<br> "); Htmlstring = Regex. Replace (Htmlstring, @ "(r | n)", "<br> "); Htmlstring = Regex. Replace (Htmlstring, @ "(s)", "& nbsp ;"); Return Htmlstring; }

This filter can be used for filtering when users enter the published content. If there are any deficiencies, Please criticize and correct them!