check url in string javascript code example

Example 1: Check if a JavaScript string is a URL

function isValidURL(string) {
  var res = string.match(/(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g);
  return (res !== null)
};

var testCase1 = "http://en.wikipedia.org/wiki/Procter_&_Gamble";

alert(isValidURL(testCase1));

Example 2: javascript url check

const isAbsoluteUrl = url => /^[a-z][a-z0-9+.-]*:/.test(url);

// Example
isAbsoluteUrl('https://1loc.dev');          // true
isAbsoluteUrl('https://1loc.dev/foo/bar');  // true
isAbsoluteUrl('1loc.dev');                  // false
isAbsoluteUrl('//1loc.dev');