JavaScript: Check whether a given value is an valid url or not

JavaScript validation with regular expression: Exercise-9 with Solution

Validate URL

Write a JavaScript function to check whether a given value is a valid URL or not.

Sample Solution:

JavaScript Code:

function is_url(str)
{
  regexp =  /^(?:(?:https?|ftp):\/\/)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,})))(?::\d{2,5})?(?:\/\S*)?$/;
        if (regexp.test(str))
        {
          return true;
        }
        else
        {
          return false;
        }
}

console.log(is_url("http://www.example.com"));
console.log(is_url("https://www.example.com"));
console.log(is_url("www.example.com"));

Output:

true
true
true

Flowchart:

Live Demo:

See the Pen javascript-regexp-exercise-8 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that uses a regular expression to validate a URL according to common standards.
• Write a JavaScript function that parses a URL and checks if it contains a valid protocol and domain.
• Write a JavaScript function that validates a URL and returns a boolean, handling both http and https.
• Write a JavaScript function that trims the input and tests it against a regex to ensure it’s a properly formatted URL.

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