title: URL Validation - Accepts URLs without protocols
body: <p>I've a basic URL validation in my appliction. Right now i'm using the following code.</p>
  
  <pre><code>//validates whether the given value is 
  //a valid URL
  function validateUrl(value)
  {
      var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&amp;%@!\-\/]))?/
      return regexp.test(value);
  }
  </code></pre>
  
  <p>But right now it is not accepting URLs without the protocol. For ex. if i provide www.google.com it is not accepting it. How can i modify the RegEx to make it accept URLs without protocol?</p>