backbone.js initialize listeners vs events

Question

I don't understand the difference between putting a "click" listener in an initialize function inside a view and putting it in the events object in the same view. They both listen for DOM events and trigger functions, right? What's the difference?

for example:

var ViewName = Backbone.View.extend({  
    initialize: function(){  
        this.$el.on("eventName", this.functionName, this)  
    },  
    functionName: function(){  
        //whatever  
    }  
});

versus:

var ViewName = Backbone.View.extend({  
    events: { "eventName": "fucntionName" }   
    },  
    functionName: function(){  
        //whatever  
    }  
});

Answer 1

When you do:

var ViewName = Backbone.View.extend({  
   initialize: function(){  
      this.$el.on("eventName", this.functionName, this)  
   },  
   functionName: function(){  
    //whatever  
   }  
});

You have to manually unbind the event when the view is being removed. So, you would have to do something like:

var ViewName = Backbone.View.extend({  
   initialize: function(){  
      this.$el.on("eventName", this.functionName, this)  
   },  
   functionName: function(){  
    //whatever  
   },
   remove: function() {
      this.$el.off("eventName", this.functionName);
      Backbone.View.prototype.remove.apply(this, arguments);
   }  
});

If you use the events hash, Backbone takes care of undelegating events when the view is removed. This is all explained in this section of the Backbone.js annotated source.