Q:

Field level Validation Rule => "OnSave"?

I need an 8 characters length enforcing validator. I created a MaxLength=8 and combined it with a MinLength=8 validation rule. 
Then I enter "1234567890123' and it's saving, no question asked! 
It does work if I click the "REVIEW" tab then "Validation". At the very bottom of a long list of schema warnings for each and every field. Our users won't do that. 
I've been researching quite a bit already. One talk about "Quick Action Bar" that I don't see anywhere, and so on. I just need a simple, text field validation like exist in any html form. You enter data wrong, it displays a message and you can't save. Period. How do you do that?
Thanks in advance!

A:

you missed to add Parameters on your validator 

Parameters are applied using a QueryString-like list like this:
[parameter]=[value]&[parameter]=[value]
The “Result” paremeter determines the default result value of a validation. 
Possible values are:
Valid = Green, everything is fine
Suggestion = Bright Orange, hmm, take a look at this
Warning = Orange, you should do something about this
Error = Red, this is an error you know
CriticalError  = Red, user is warned before saving
FatalError = Red, user cannot save item before validator is cleared
More informations you can find here. 

A:

As well as using a rules engine based validator, there are also validation fields on the Field template that you can use:

The Validation field takes a regex and the ValidationText field can be used for the warning text. Using the following regex:
/^.{8,}$/

That makes sure that the content has a minimum length of 8 characters. Now when the content editor tries to save an item that fails that validation, the message will be shown and the user cannot save the item:

This can be a simpler setup than rules based validation, although it is limited to what you can do with a single regex statement.

