Chrome Extension: Access to frame elements - dom

Question

I am developing a chrome extension (content script) to access web page content. I use the DOM to access all elements in page.
My code does not work correctly when the web page contains "frameset". In this matter I can count the frame number but I can't access to the frame content.
I use this code to count frame objects available on current page :
for frameset :
parent.frames.length
and for iframe :
document.getElementsByTagName("iframe").length
but the following code does not work :
parent.frames[0]
and returns "undefined".
My question:
How can I access to frame set elements inside a chrome extension (for both iframe and frameset)?

Answer 1

Similar to how Jerinaw approached it, I did the following via jQuery:
// Find the frame
var frame = $(document).find("frame[name='nameOfFrame']")[0];
// Callback once frame's internals are loaded
$(frame).load(function() {
accessFrame();
});
function accessFrame() {
// The following line is really important to accessing the frame's content.
var frameContent = frame.contentDocument;
// Notice that $(".objectSelectorClass") won't discover the object you're hunting for. You have to find it within the frame's contentDocument.
var objectInFrame = $(frameContent).find(".objectSelectorClass");
var objectInFrame_AlternateSyntax = $(".objectSelectorClass", frameContent)
// do stuff to objectInFrame
}

Answer 2

I'm running into the same problem. The frames are not iframes and they are in a frameset. What I had to do was an onload (for some reason addEventListener isn't working) to the frame but through it's contentWindow
for example:
From the main document
document.querySelector('#SomeFrameSelector').contentWindow.document.body.onload
Accessing the frame this way got me to the frames document and allowed me to attach the onload. Once fired using the same selector I was able to modify the frames content.