title: Ext.form.field.HtmlEditor - get only visible text
body: <p>I have an <strong>Ext.form.field.HtmlEditor</strong>-textfield with really <strong>long text</strong> inside it and I want to save only the <strong>currently visible</strong> portion of the text inside a variable.</p>
  
  <p>For example:</p>
  
  <pre><code>var really_long_string = "...";
  var html_editor = Ext.create('Ext.form.HtmlEditor', {
      renderTo: Ext.getBody(),
      value: really_long_string 
  });
  
  var currently_visible = get_currently_visible_text_from_html_editor();
  </code></pre>
  
  <p>I don't think there are methods which do this, so I came up with an idea of calculating it myself doing these steps:</p>
  
  <p>1.) get current size of the html_editor inside a 'resize' event-handler<br/>
  2.) get the current scrollbar position of the html_editor<br/>
  3.) calculate how many lines are visible, and find them using the scrollbar position<br/></p>
  
  <p><strong>My Questions:</strong></p>
  
  <p><strong>1.) Is there an ExtJs function which gives me the current scrollbar position of the html_editor-textfield?</strong></p>
  
  <p><strong>2.) Does anyone have a better idea, how to get the visible portion of long text?</strong></p>