How to change iframe content in dom using firefox extension code?

Question

I would like to change the page shown in my browser using the Firefox extension (add-in) that I wrote. I can get iframes pages as XPCNativeWrapper using:

iframes = window.content.document.getElementsByTagName('iframe')

for (var i = 0; i < iframes.length; i++) {
  var elmInput = iframes[i];
  Firebug.Console.log(elmInput);
}

But I could not get to the contents of iframes, not to mention changing it.

How can I change the contents of an iframe in dom?

Answer 1

I think you want elmInput.contentDocument

Answer 2

for (var i = 0; i < iframes.length; i++) {
    var content = iframes[i].contentWindow.document.body.innerHTML;
    ...
}