document.write statement, the simple, non-blocking solution detailed below may work for you.
In the body of the page, place the following code where you would like the widget to appear:
<div id="contentad[Your WID value]"></div><!-- Load Widget Here --></div>
If you are unable to add HTML to the page:
Skip the second step, and change the line
document.getElementById("contentad[Your WID value]").appendChild(s); so that the value of getElementById is the ID of an element currently on the page inside of which you would like the widget to appear.