Nick Kaijaks

I've got this [working in a fork](https://github.com/nanoamp/openhtmltopdf/tree/custom-marker-support). Some issues with alignment which mean it's not quite MR-ready, but you're welcome to try it.

It's probably a bit late now, but there's a response to another issue - https://github.com/freewil/express-form/issues/2 - which provides a possible solution by using something like ``` form.field('field2').custom(function(value, source) { if...

Ah, now I see what you mean. You're welcome to try the [fork](https://github.com/UniversityofWarwick/express-form) I've been working on today, to which I've added a `.validateCustomIfEmpty()` method. I'll probably pull-request it to...