javascript validation for url using regular expression

[smiley_kool]

hi ,

    i need a JS validation for url with regular expression , which should allow the following ways

 

http://google.com

http://www.google.com

www.google.com

 

[Axeia]

Call me crazy, but if you're going to offer 3 options use a select?

<select name='google'>
  <option>http://google.com</option>
  <option>http://www.google.com</option>
  <option>www.google.com</option>
</select>

Or just compare the entire string

function isValidGoogle( str )
{
  return ( str == http://google.com || str == http://www.google.com || str == www.google.com );
}

 

If you know enough javascript to think of regular expression you'd probably thought of either of those two yourself, so exactly how are you going to use it? Need more info.