I would like to improve the validation "output" of XForms in general... I would like the fields to change color if they are not filled correctly. Does anyone here have a good idea of how to go about this? I'm using webforms and EPiServer 7.5. Thankful for help!
I would've adviced you to use the standard HTML5 validation attributes when customizing output of your xforms.
But right now the new Episerver Forms just came out which you should take a look at before starting any work with xforms.