Coming from XF, I'm assuming you want something like XenPorta, to display topics as a blog. I'm working on such a plugin here. It's not even close to finished, but it may be all you need. I use it on my own forum here.
I have several number and string fields in my plugin-rendered page through a custom template edit_info.tpl.
Everything is working fine and wanted to add some validations for the fields before submitting.
What would be the best way to achieve this?