EllisLab/CodeIgniter — pull request #968 by atiredmachine (2012-01-25 11:01:15+00:00)
Title: Valid_url form_validation rule

I thought this was a good idea.

Wasn't sure how strict it should be. For example, should "bit.ly/goo" return TRUE or FALSE? (a question of whether http(s):// should be required...)