title: Count or Select Backbone View Instances
body: <p>Let's say I'm trying to create a toDo application, where clicking each toDo opens an edit form for each toDoItem. I only want a maximum of one edit form open at any one time, so right now I am doing this in the edit method of the toDoItem view:</p>
  
  <pre><code>edit: function (e) {
    e.preventDefault();    
    if ($('.editForm').length == 0)  {
      //create form model and view
    }
  }
  </code></pre>
  
  <p>That works, but doesn't seem very Backbone-y. Is there are way to select or count all instances of a particular view (in this case, the form-view)?</p>