How to create transparent frameset?

Question

I want to create a page with 3 frames in a frameset.

My Home.html is the main page, with 3 frames, which is Header.html, Announcement.php and Footer.html.

<frameset rows="10%,*,5%" noresize frameborder="NO" FRAMESPACING="0" scrolling="NO" >
   <frame src="Header.html" scrolling="NO">
   <frame src="Announcement.php" name="container">
   <frame src="Footer.html" scrolling="NO">
</frameset><noframes></noframes>

Inside the Header.html, I defined the style of the html to transparent inside the Frame.css. This same to the others 2 frames as well.

html
{
    background-color : transparent;
}

But the background of the Home.html does not display. But when I remove the frameset, the background is displayed.

I uploaded it to here.

So how can I solve this problem?

Edit :

Based on this page, is the allowtransparency attribute browser dependability?

Solve :

I'm tried to view the page with Mozilla Firefox, it seems like working with allowtransparency attribute, but when I view the page using chrome, IE9 and Opera 12, it's didn't work.

Answer 1

Try settting

<frame allowtransparency="true">

http://www.webreference.com/js/tips/010209.html

Answer 2

Use:

<frame allowtransparency="true" ...>