How do i find if the model is new or has no property in it : backbone

How do i find if the model is new or has no property in it : backbone

This is my backbone model and collection:
var myModel = Backbone.Model.extend({ });
var myCollection = Backbone.Collection.extend({
model : myModel,
});
when i do new of model
debitRow = new myModel();
this will have no property or value in it.
now how do i find that the model is empty or not