Develop custom Javascript html editor
<p>I want to develop a custom javascript html editor. My starting point was: 
<a href="http://hypertextarea.sourceforge.net/" rel="nofollow">http://hypertextarea.sourceforge.net/</a></p>

<p>I understood how the mechanism works but the problem is that I cannot find the point where if I focus the iframe I have the cursor displayed. </p>

<p>Then if I press a key I see the letter entered there. Can you please explain me how this javascript shows the editor cursor and how it write in the iframe the characters that I write?</p>

<p>All javascript used by this editor is at 
<a href="http://hypertextarea.sourceforge.net/javascript/HyperTextArea.js" rel="nofollow">http://hypertextarea.sourceforge.net/javascript/HyperTextArea.js</a></p>
