While the attributes property is (behind the scenes) just a JavaScript object, that doesn't mean that we should treat it as such. For instance, you should never set an attribute directly by changing the attributes property of a Model class:

var book = new Book({pages: 200});
book.attributes.pages = 100; // don't do this!

Instead, the attributes of Backbone's Models should be set using the Model's set method:

book.set('pages', 100); // do this!

The set method has two forms or signatures. The first (shown previously) takes two arguments: one for the data's key and one for its value. This form is great if you only want to set one value at a time, but if you need to set multiple values, you can use the second form instead, which takes only a single argument containing all the values of set:

book.set({pages: 50, currentPage: 49});

In addition, Models also have an unset method, which takes only a single key argument and works in a similar way as JavaScript's delete statement, except...