title: How to replace an element with TinyMCE
body: <p>I'm using TinyMCE and i'm creating a new plugin.</p>
  
  <p>I need, in this plugin, to replace something i have selected in the text by an other thing.</p>
  
  <p>With this : <code>var inst = tinyMCE.activeEditor;</code> i can have a instance of my editor.</p>
  
  <p>How can i retrieve my selection ? How can i replace my selection by, for example <code>&lt;span&gt;MYSELECTION&lt;/span&gt;</code> ?</p>
  
  <p>Thanks !</p>