Edit in JSFiddle

var testView1 = Backbone.View.extend({
  el: '#content',
  defaults: {
      today: {year: 2012, month: 1, day: 1}
  },
  events: {
      'click #todayWeatherBtn': 'alertWeather'
  },
  initialize: function() {
    console.log('testView1をnewした時に、実行されます。基本初期設定などを行う為に使います。');

      
      this.today = this.defaults.today;
      if (this.options.today !== undefined) {
          this.today = this.options.today;
      }
      
  },
  render: function() {
    var text = this.today.year + '年'
               + this.today.month + '月'
               + this.today.day + '日の天気は';
      
    $('#view').append('<button id="todayWeatherBtn">'+text+'</button><br>');
    return 'testView1のrenderです。';
  },
  alertWeather: function() {
      if (this.today.year === 2012) {
          alert('晴');
      } 
      else
      {
          alert('雨');
      }
  }
});


var today = {
    year: 2013,
    month: 8,
    day: 21
};

var test_view1 = new testView1({today: today});
test_view1.render();
/*
var test_view1 = new testView1();
test_view1.render();
*/
<div id="content"> 
  <div id="view"></div>
  
</div>
</style> <!-- Ugly Hack due to jsFiddle issue: http://goo.gl/BUfGZ -->
<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//underscorejs.org/underscore-min.js"></script>
<script src="//backbonejs.org/backbone-min.js"></script>
<style>