Ok, this is considerably more complex then you first description of your page.
You are not loading an iframe, you seem to be trying to make webbased editor and the code is prettyu banged up.
For starters, this is what your iframe looks like
<font size="2" face="Verdana, Helvetica"></font>
That is VERY far from how a HTML page should look like, which is something like this
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta http-equiv="Content-Style-Type" content="text/css">
However are you sure you are not really looking for the <textarea> tag instead of an <iframe> ?