Accessing sjavascript in parent window from within an embedded svg

I embedded an svg document in an HTML page. One of the svg elements has a "onmouseover=toggle(evt)" event handler. If I place the "toggle(evt)" function in the top HTML page, I am getting "toggle is not defined error" in Mozilla Firefox.

If I place the "toggle" function in the svg document itself, the function is being recognized and called. However, the "toggle" function needs to fire another script in the main HTML page.

How do I access the script in parent window from within the embedded svg?

The following is not working..

    var elem = evt.target.ownerDocument.parentNode;   // returns undefined

   or
   
   var elem = evt.target.ownerDocument.contentWindow;   // returns null.

Please help !!!

Vyas Vemu