Custom product attribute or custom productpage

Can someone help me in the right direction with the following?

I want to check the input of certain textfields (product attributes) on the productpage and depending on the input I want to execute some logic / show warnings / etc.

I would like to do this with a plugin and do not want to touch the core. I'm not sure on how to approach this. Can I just write a plugin that handles this part of the productpage or should I build a plugin for a whole new productpage.

I both cases I would like to know the steps for doing this. I wrote some plugins before but unfortunately I cannot figure out how to do this. (I already checked the manuals/forums and goole but with no result)

Thank you for your help!

Found a solution, maybe interesting for others having the same issue.

Made a custom viewengine in my plugin, this custom viewengine adds a location to search for views and this is the location of the views in the plugin. Now I can override every view and partial view without any problem.

Ran into an extra problem because I used a theme from someone else, my views where not showing, for that the solution is here:

https://www.nopcommerce.com/boards/t/41688/override-seven-spikes-core-plugin.aspx