How to validate url?

Question

I want to validate urls. It should accept:

http://google.com

http://www.google.com

www.google.com

google.com

I refer Regex to match URL

Answer 1

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