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

Last update on May 30 2022 10:02:54 (UTC/GMT +8 hours)

JavaScript validation with regular expression: Exercise-9 with Solution

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

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to check whether a given value is an url or not</title>
</head>
<body>

</body>
</html>

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

Sample Output:

true
true
true

Flowchart:

Live Demo:

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

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Next: Write a JavaScript function to check whether a given value is alpha numeric or not.

JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04