Question

here is my form: can i set validation rules inside this definition or have i
to validate over it by hand with conditional statements or is something like this already build in?

i would like to set for learning purposes the minlength to 20 without conditionals of my own.
or shall i extend the plugin by including them in the plugin file?

var form1 = new Backbone.Form({
schema: {
    country: { type: 'Select', options: ['UK', 'USA'] },
    city: { type: 'Select', options: cities.UK },
    message: { validators: ['required', 'message'] }
}

}).render();

Answer 1

You can define a minimum length rule as a regular expression:

message: { validators: [ 'required', /.{20,}/ ] }

All the validation options are documented here.