Javascript: check if an url is valid and starts with "http//" or "https://"

Question

I want to test my urls validity , which should start with http:// or https:// ,

i ve used this RegExp :

private testIfValidURL(str) {
    const 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);
  }

This would work , execpt one case :

To consider it as valid , my urls should always start with http:// or https:// , but with my function , urls like www.abcd.com would be treated as valid urls which is not enough for me.

Sugesstions ?

What is a "valid" url for you?

Toto
– Toto

2019-03-14 12:52:19 +00:00
Commented Mar 14, 2019 at 12:52 — Toto
– Toto, Commented Mar 14, 2019 at 12:52

Michał Turczyn · Accepted Answer · 2019-03-14 12:43:31Z

1

Just change ^(https?:\\/\\/)?' to ^(https?:\\/\\/)', the ? means that you want to match zero or one occurnece of a pattern. You actually want exactly one occurence, so don't use ? :)

From regular-expressions:

? - Makes the preceding item optional. Greedy, so the optional item is included in the match if possible.

answered Mar 14, 2019 at 12:43

Michał Turczyn

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Orelsanpls · Accepted Answer · 2019-03-14 12:44:14Z

1

You can remove the (...)? chars, so it will be mandatory to have a http or https sequence first.

function testIfValidURL(str) {
  const 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);
}

console.log(testIfValidURL('www.abcd.com'));
console.log(testIfValidURL('http://www.abcd.com'));
console.log(testIfValidURL('https://www.abcd.com'));
console.log(testIfValidURL('htt://www.abcd.com'));

answered Mar 14, 2019 at 12:44

Orelsanpls

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