We can write the methods which contain the business logic.

SEE the EXAMPLE below:

Person = Backbone.Model.extend({
DEFAULTS: {
name: 'Fetus',
age: 0,
child: ''
},
initialize: function(){
alert("This class has adop() method which contains business logic to set new child.");
},
adopt: function( newChildsName ){
this.set({ child: newChildsName });
}
});

VAR person = new Person({ name: "Thomas", age: 67, child: 'Ryan'});
person.adopt('John Resig');
 var child = person.get("child"); // 'John Resig'

We can write the methods which contain the business logic.

See the example below:

Person = Backbone.Model.extend({
defaults: {
name: 'Fetus',
age: 0,
child: ''
},
initialize: function(){
alert("This class has adop() method which contains business logic to set new child.");
},
adopt: function( newChildsName ){
this.set({ child: newChildsName });
}
});

var person = new Person({ name: "Thomas", age: 67, child: 'Ryan'});
person.adopt('John Resig');
 var child = person.get("child"); // 'John Resig'