JAVASCRIPT

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}([-a-zA-Z0-9@:%_+.~#?&//=]*)/g);
  return (res !== null)
};

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

alert(isValidURL(testCase1)); 

check-if-a-javascript-string-is-a-url

  const isUrl = string => {
      try { return Boolean(new URL(string)); }
      catch(e){ return false; }
  }