How do I add a resize event to the window in a view using Backbone?

var BaseView = Backbone.View.extend({

    el: $('body'),

    initialize: function() {
        // bind to the namespaced (for easier unbinding) event
        // in jQuery 1.7+ use .on(...)
        $(window).bind("resize.app", _.bind(this.resize, this));
    },

    remove: function() {
        // unbind the namespaced event (to prevent accidentally unbinding some
        // other resize events from other code in your app
        // in jQuery 1.7+ use .off(...)
        $(window).unbind("resize.app");

        // don't forget to call the original remove() function
        Backbone.View.prototype.remove.call(this);
        // could also be written as:
        // this.constructor.__super__.remove.call(this);
    }, ...

Don't forget to call the remove() function on the view. Never just replace the view with another one.

You might let window.onresize trigger a custom backbone.js event and then let Views or Models listen to that to have custom responses for various elements.

Case 1. A view listens to the window event directly.

window.onload = function() {

  _.extend(window, Backbone.Events);
  window.onresize = function() { window.trigger('resize') };

  ViewDirect = Backbone.View.extend({

    initialize: function() {
      this.listenTo(window, 'resize', _.debounce(this.print));
    },

    print: function() {
      console.log('Window width, heigth: %s, %s',
        window.innerWidth,
        window.innerHeight);
    },

  });

  var myview = new ViewDirect();

  }

Case 2. You may want to retain the window size without inspecting it each time you need it, hence you store the window size in a backbone model: in this case the window model listens to the window, while the view listens to the window model:

window.onload = function() {

  _.extend(window, Backbone.Events);
  window.onresize = function() { window.trigger('resize') };

  WindowModel = Backbone.Model.extend({

    initialize: function() {
      this.set_size();
      this.listenTo(window, 'resize', _.debounce(this.set_size));
    },

    set_size: function() {
      this.set({
        width: window.innerWidth,
        height: window.innerHeight
      });
    }

  });

  ViewWithModel = Backbone.View.extend({

    initialize: function() {
      this.listenTo(this.model, 'change', this.print);
      ...
    },

    print: function() {
      console.log('Window width, heigth: %s, %s',
        this.model.width,
        this.model.height);
    },
  });

  var window_model = new WindowModel();
  var myview = new ViewWithModel({model: window_model});

}