How to Remove All HTML Tags from a String Without Knowing Which Tags Are in It

How do I remove all HTML tags from a string without knowing which tags are in it?

You can use a simple regex like this:

public static string StripHTML(string input)
{
   return Regex.Replace(input, "<.*?>", String.Empty);
}

Be aware that this solution has its own flaw. See Remove HTML tags in String for more information (especially the comments of 'Mark E. Haase'/@mehaase)

Another solution would be to use the HTML Agility Pack.

You can find an example using the library here: HTML agility pack - removing unwanted tags without removing content?

How to remove HTML tag (not a specific tag ) with content from a string in javascript

Removing all HTML tags and the innerText can be done with the following snippet. The Regexp captures the opening tag's name, then matches all content between the opening and closing tags, then uses the captured tag name to match the closing tag.

const regexForStripHTML = /<([^</> ]+)[^<>]*?>[^<>]*?<\/\1> */gi;
const text = "OCEP <sup>®</sup> water product";
const stripContent = text.replaceAll(regexForStripHTML, '');
console.log(text);
console.log(stripContent);

How to remove html tags from string in view page C#

If you want to show your content without any formatting then you can use this Regex.Replace(input, "<.*?>", String.Empty) to strip all of Html tags from your string.

1) Add below code to top of view (.cshtml).

@using System.Text.RegularExpressions;

@helper StripHTML(string input)
{
    if (!string.IsNullOrEmpty(input))
    {
        input = Regex.Replace(input, "<.*?>", String.Empty);
        <span>@input</span>
    }
}

2) Use the above helper function like

<td>@StripHTML(item.Message)</td>

How can I remove HTML tags other than div and span from a string in JavaScript?

To remove all tags excluding specific tags, you can use the following regular expression.

const str = "<div><p></p><span></span></div>";
console.log(str.replace(/(<\/?(?:span|div)[^>]*>)|<[^>]+>/ig, '$1'));

Remove HTML tags from a String

Use a HTML parser instead of regex. This is dead simple with Jsoup.

public static String html2text(String html) {
    return Jsoup.parse(html).text();
}

Jsoup also supports removing HTML tags against a customizable whitelist, which is very useful if you want to allow only e.g. <b>, <i> and <u>.