Check if a JavaScript string is a URL

Question

Is there a way in JavaScript to check if a string is a URL?

RegExes are excluded because the URL is most likely written like stackoverflow; that is to say that it might not have a .com, www or http.

Answer 1

If you want to check whether a string is valid HTTP URL, you can use URL constructor (it will throw on malformed string):

function isValidHttpUrl(string) {   let url;      try {     url = new URL(string);   } catch (_) {     return false;     }    return url.protocol === "http:" || url.protocol === "https:"; } 

Note: Per RFC 3886, URL must begin with a scheme (not limited to http/https), e. g.:

• www.example.com is not valid URL (missing scheme)
• javascript:void(0) is valid URL, although not an HTTP one
• http://.. is valid URL with the host being .. (whether it resolves depends on your DNS)
• https://example..com is valid URL, same as above

Answer 2

A related question with an answer

Or this Regexp from Devshed:

function validURL(str) {   var pattern = new RegExp('^(https?:\\/\\/)?'+ // protocol     '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name     '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address     '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path     '(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string     '(\\#[-a-z\\d_]*)?$','i'); // fragment locator   return !!pattern.test(str); }