Valid url check in form validation

[eluser]Mike Ryan[/eluser]
Hi Iverson,

Great contribution, I have always been a little surprised that this function was not included as a built-in rule. This will be useful on a current project, so thank you.

You included a match for the port specification... nice!

I did find one bug - this regex will match "www.domain.co.u-k".

There's a great online regex tester here. The site also has some great examples of regexs, including some good ones for URLs (neither of which are perfect):

Code:

/(((http|ftp|https):\/\/){1}([a-zA-Z0-9_-]+)(\.[a-zA-Z0-9_-]+)+([\S,:\/\.\?=a-zA-Z0-9_-]+))/igs
/^((ht|f)tp(s?)\:\/\/|~/|/)?([w]{2}([\w\-]+\.)+([\w]{2,5}))?(:[\d]{1,5})?+([a-zA-Z0-9\/\_\?\.\,\&]+)?/