createTextRange and Input Boxes

Hi,
I am trying to create a find and replace function on my HTML page. I can
easily search the body of the document using the following code:

var rng = document.body.createTextRange();
rng.findText( ... ) etc

However the range does not include the text from input type="text"
objects. Is there anyway that I can include them in one textrange object?

Thanks,
Sam