How To Use "document.write()" To Output An Entire Webpage?

I'm trying to create output a webpage HTML using javascript, but I don't know how to make it work because of the quotes problems.

I am calling the javascript you see below from within a window that is created by my PHP script. The window contains two frames, and I want the "previewFrame" to contain the HTML code that is located inside the $preview_HTML php variable.

(The $preview_HTML variable contains all the HTML for the webpage. No quotes are escaped. It is just a string variable with the webpage contents in it.) I hope that makes sense.

HTML Code:

<script language="JavaScript">

function loaded() {

parent.previewFrame.document.open();
parent.previewFrame.document.write('<h1>Hello World</h1>');
parent.previewFrame.document.write('<?=$preview_HTML?>');
parent.previewFrame.document.close();

}</script>

The problem is that all the quotes inside the $preview_HTML variable is causing this javascript to fail. I either end up with a blank page, or partial page, or just garbage, depending on the HTML code inside the $preview_HTML variable.

Basically, I just want to "write" the entire contents of the $preview_HTML variable without having to "worry" about escaping quotes, slashes, etc.