Input Controls - Dependant values and validation

Ability to represent two controls that depend on each other. For example :

_ Representation of date ranges (date1 <= date2)

_ Representation of interval values (value1 <= value2)

_ Validate this field only if the field 'x' is checked

Thefore the ability to add validation rules to dependant input controls is a must.

A good example of such validation is defined in Struts validators "validwhen"

http://struts.apache.org/1.x/faqs/validator.html