How to show overlay across FRAMES?

Suppose I have following frame structure.

<frameset rows="20%,60%, *">
  <frame name="theFrame" id="theFrame" src="test1.html" >
  <frame name="theSecondFrame" id="theSecondFrame" src="test2.html" >
  <frame name="importantFrame" id="importantFrame" src="test3.html" >
</frameset>

Suppose in "theSecondFrame" i have a button and if I c开发者_如何转开发lick on that button it should show a modal window.

The problem I am facing is, overlay is only limited to "theSecondFrame".

How to spread overlay across all frames so that contents are not accessible?

It's not possible to render HTML elements across multiple frames in a frameset. Each frameset is defined in the browser as having its own viewport boundary, and that means you won't be able to position stuff outside the boundaries and have them show across frames.