Check if url is valid or not

Question

I tried to check if url is valid or invalid. the checks of 7,8 returns wrong outputs.

alert('1: ' + learnRegExp('http://www.google-com.123.com')); // true
alert('2: ' + learnRegExp('http://www.google-com.123')); // false
alert('3: ' + learnRegExp('https://www.google-com.com')); // true
alert('4: ' + learnRegExp('http://google-com.com')); // true
alert('5: ' + learnRegExp('http://google.com')); //true
alert('6: ' + learnRegExp('google.com')); //true
alert('7: ' + learnRegExp('ww.google.com')); //false -> it returns true
alert('8: ' + learnRegExp('www.google.co.il')); //true -> it returns false
alert('9: ' + learnRegExp('http://ww.google.co.il')); //false
alert('10: ' + learnRegExp('https://ww.google.co.il')); //false

function learnRegExp(){
    return /((ftp|https?):\/\/)?(www\.)?[a-z0-9\-\.]{3,}\.[a-z]{3}$/
    .test(learnRegExp.arguments[0]);
}

please help me to solve it.

any help appreciated!

Remember that `www` is just a subdomain. I wouldn't bother explicitly including that in the regex. — David Sherret, Jul 18 '13 at 14:38
A lot of things can be a valid URL e.g. `http://xyz.mysite.org.ru` I guess the real test would be try and load it — Yuriy Galanter, Jul 18 '13 at 14:40
Your regex validates `.--.wkh` or `6-..oqw` but rejects `google.fr`. — sp00m, Jul 18 '13 at 14:48
I would say that this question is distinct from the proposed duplicate, as ECMA and PHP do use two different flavors of Regular Expressions. — Chris Sobolewski, Jul 18 '13 at 14:52

score 7 · Accepted Answer · edited Jun 08 '15 at 13:49

7

Try this one:

 function learnRegExp(s) {    
      var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
      return regexp.test(s);    
 }

edited Jun 08 '15 at 13:49

trejder

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answered Jul 18 '13 at 14:56

Ishan Jain

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Unfortunately this runs 'true' for learnRegExp("http://fgsdfjgd") as well, which should be 'false' – patrick Mar 11 '14 at 21:54
It's fine now, just take note that `s` must be in lowercase. – Joyce Mar 19 '18 at 07:55

score 0 · Answer 2 · edited May 23 '17 at 12:29

0

Problem with 7 is (www\.)? is allows 0 or 1 www. and [a-z0-9\-\.] allows . Since it's only ww. then (www\.)? treats it as 0 and [a-z0-9\-\.] captures the ww..

Problem with 8 is \.[a-z]{3} only allows for .com, .net, etc. It forces the string after the last . to be 3 characters long. Since it's only 2 characters, it doesn't match.

Don't try to recreate the wheel: What is the best regular expression to check if a string is a valid URL?

edited May 23 '17 at 12:29

Community

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answered Jul 18 '13 at 14:42

basher

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unfortunately the RegExp on that page is in PHP, not in JavaScript as was asked... – patrick Mar 11 '14 at 21:42

Check if url is valid or not

2 Answers2

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