CODE EXAMPLE FOR JAVASCRIPT

regex for url

// All are 'non-capturing' regular expressions.

// General format of a URL in a RegEx:
(?:(?:https?|ftp)://)?(?:www.)?[^/
]+(?:/[^
]*)?

// To enforce the protocol
(?:https?|ftp)://(?:www.)?[^/
]+

// To enforce the protocol and trailing slash
(?:https?|ftp)://(?:www.)?[^/
]+(?:/[^
]*)

// To enforce file extensions like .html or .png:
(?:(?:https?|ftp)://)?(?:www.)?[^/
]+(?:/[^
]*)(?:[a-zA-Z0-9]+.(?:html|png|webp|js))

// To implement in GO (https://go.dev), add an extra backslash ('  ') to every unescaped backslash ('  ')

// For the first format, that is:
(?:(?:https?|ftp)://)?(?:www.)?[^/
]+(?:/[^
]*)?

// You do not need to add the extra backslash to the '
' and '
' because it is handled natively