Disable groups on form load

[Ecovoyageurs]

Hi,
Do you know if there is a way to disable groups on form load based on the value of a field X ?
Best way would be to use a PHP plugin onbeforeload and tell that if the field X = a certain value, groups y and z should be "read only" before rendering... but is it doable ?
Another way would be with js and disable all fields onload but then it's still possible to change the fields values with urls params or some hacky technics...
Thanks for your help !

 

[troester]

I would
disable the groups via JS on load
add a php plugin onBeforeStore comparing original data with data on save, restoring original data if modified (and ban user)

 

[Ecovoyageurs]

Well... I can't really ban the user as it's my customer ! ;-)

The system is a quote/invoice form.
When it has a quote status, we still can modify, but when the status is changed to invoice, we have to make it read only.
More than this... the French administration (tired of them...) has stated that invoicing applications editors now have to prove that the invoices are really uneditable.

See why I would prefer a PHP onbeforething solution...