> Why use regex? It's much simpler to write a URL validator by hand... I actually have a use-case. I am firming up a feature right now that detects when a user

> Why use regex? It's much simpler to write a URL validator by hand... I actually have a use-case. I am firming up a feature right now that detects when a user types a url into a text field and replaces it on the fly with a footnote-style reference number (much like your comment above). This is done to (1) minimize input string length, (2) draw the benefits of a consistent interface, and (3) avoid screwing around with the fragility of url shortening nonsense. I may regret this, but here's a link to my dev environment for this feature (please be gentle), to see it in action: https://cloudcity.tenfourgood.com/cloudcity https://cloudcity.tenfourgood.com/cloudcity ...just start typing in the big text box and add in some urls. It uses a fairly ugly-looking regular expression[0]. If you take out the unicode mumbojumbo, it's not really THAT tricky of a pattern. It does fail on IP addresses and it may be a little over-aggressive on matching, but, I wanted it to catch things like "abc.com" and "//xyz.com". Edit: Formatting and clarity. Removed the explicit regular expression because it predictably got garbled. [0] http://regexr.com/38vsq http://regexr.com/38vsq not exactly the same one I'm currently using, but it's pretty close. See source for most up-to-date version.