Inline validation documentation

Where can I find info about (pat) inline validation.

Is it possible to for example validate that a number is between 1950 and 2015? Or that the field is one word and one number ?

According to https://docs.plone.org/external/plone.app.dexterity/docs/reference/fields.html an intfield support IMinMax, so you can set min=150 and max=2015 in the field definition in your schema.
For example:

year_or_birth = zope.schema.Int(
    title=u'My field',
    description=u'My great field',
    min=0,
    max=100,
    default=50,
)

So it can only be used og I have a skjema ? (I dont )

You can set it via the DX types controlpanel as well

Probably I am misunderstanding what 'inline validation' means.

I dont have a schema or a content type. I thought it was possible to have an input field 'with plain html' and use pat inline validation to validate.

My usecase would be (similar to) having a widget with 3 inputs for dates ( Year, Month, Day of Month and save it 'to one field'. (Like this: https://www.youtube.com/watch?v=k3n6PjDLAj0 )

See https://patternslib.com/validation

That looks like what I was looking for. Thanks a lot