Use readonly and invisible in 1 field openerp

Question

How to use readonly and invisible in 1 field using attrs in openerp ?Just likes I have field 'country'. I want this field read only if a==b and invisible if c==d .

Answer 1

Attributes on fields:

<... attrs = "{'readonly': [('field_a','=','field_b')],'invisible':[('field_c','=','field_d')]}" .../>

Please provide some more information about what a,b,c and d are.