map.openInfoWindow(map.getCenter(),
document.createTextNode('[HTML]<div style="width:200px">Hello Joe</div>

'));[/HTML]

I am playing around with a google map and want to put a div tag to style "Hello Joe" have no given it a ID or class yet, just put a inline style to see it if works.

But what I get back is

<div style="width:200px">Hello Joe</div>

And not Hello Joe.

What am I doing wrong?

At a guess, I would say that the createTextNode function does exactly that, creates text. Look for the function for HTML

Set empty div on place where you want your text to be with ID and then access/modify InnerHtml of the element via JavaScript...

document.getElementById('yourelementid').innerHTML = 'Fred Flinstone';