JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://documentcloud.github.com/underscore/underscore-min.js"></script>
<script src="http://documentcloud.github.com/backbone/backbone-min.js"></script>
<script id="script_content" type="text/template">
 <ul><li><%= notification_num %></li></ul>
   </script>
     
   <script id="script_content2" type="text/template">
 <div id="test">CLICK HERE</div>
   </script>
<div id="content"></div>
    <div id="content2"></div>

JavaScript

(function($){

    window.LeftNotificationModel = Backbone.Model.extend({
        
        defaults:{
            'notification_num':12
        },
        
        initialize: function() {    
        },
        
        decrementNotification: function() {
            alert(this.get('notification_num'));
            notification_num = this.get('notification_num');
            notification_num = notification_num -1;
            this.set({'notification_num': notification_num });
        }
    });
    
})(jQuery); 
    
(function($){

    window.LeftNotificationView = Backbone.View.extend({
        
        initialize: function () {
            _.bindAll(this,    'render');
            this.model.bind('change:notification_num', this.render);
        },
        
        render: function() {
            template= _.template($('#script_content').html());
            $(this.el).html(template(this.model.toJSON()));
            $('#content').html(this.el);
        }
    });
          
    window.PopupView = Backbone.View.extend({
        
        events: {
            'click #test': 'decrementNotification'
        },
        
        initialize: function () {
            this.model.bind('change:notification_num', this.render);
        },
        
        render: function() {
            template= _.template($('#script_content2').html());
            $(this.el).html(template(this.model.toJSON()));
            $('#content2').html(this.el);
        },
        
        decrementNotification: function() {
            this.model.decrementNotification();
        }
    });

})(jQuery); 

$(document).ready(function() {
    var model = new LeftNotificationModel();

    window.LeftNotificationView = new LeftNotificationView({ model: model});
    window.LeftNotificationView.render();
    window.PopupView = new PopupView({ model: model});
    window.PopupView.render();
});