I need to be able to check that the domain entered into a field is in the valid format of a domain, which I'm sure can be done using a regular expression, but its not exactly something I've ever understood!

If someone could help me out on this that would be great, thanks!

I think you need to use the indexOf jscript.

well, u can do it but there are many versions of a url.

you got for instance:

www.blah.com
www.something.us
subdomain.crap.yahoo.co.uk

and that's just to name a few.

also, remember that you can have numbers and underscores and hyphens in that sequence of characters as well. you can also have an IP point to a domain.

it would be simple to catch www.my_domain-is-no1.com ... we could even catch diff extensions like us and com together...

/www\.[a-z0-9_\-]+\.[a-z]{2, 3}/ig.test(string)

but the rest.. well, i suppose if you new EVERY form of the URI possible, we could go from there