What's the most concise cross-browser way to access an <iframe> element's window and document?
- by Bungle
I'm trying to figure out the best way to access an <iframe> element's window and document properties from a parent page. The <iframe> may be created via JavaScript or accessed via a reference stored in an object property or a variable, so, if I understand correctly, that rules out the use of document.frames.
I've seen this done a number of ways, but I'm unsure about the best approach. Given an <iframe> created in this way:
var iframe = document.createElement('iframe');
document.getElementsByTagName('body')[0].appendChild(iframe);
I'm currently using this to access the document, and it seems to work OK across the major browsers:
var doc = iframe.contentWindow || iframe.contentDocument;
if (doc.document) {
doc = doc.document;
}
I've also see this approach:
var iframe = document.getElementById('my_iframe');
iframe = (iframe.contentWindow) ? iframe.contentWindow :
(iframe.contentDocument.document) ? iframe.contentDocument.document :
iframe.contentDocument;
iframe.document.open();
iframe.document.write('Hello World!');
iframe.document.close();
That confuses me, since it seems that if iframe.contentDocument.document is defined, you're going to end up trying to access iframe.contentDocument.document.document.
There's also this:
var frame_ref = document.getElementsByTagName('iframe')[0];
var iframe_doc = frame_ref.contentWindow ? frame_ref.contentWindow.document :
frame_ref.contentDocument;
In the end, I guess I'm confused as to which properties hold which properties, whether contentDocument is equivalent to document or whether there is such a property as contentDocument.document, etc.
Can anyone point me to an accurate/timely reference on these properties, or give a quick briefing on how to efficiently access an <iframe>'s window and document properties in a cross-browser way (without the use of jQuery or other libraries)?
Thanks for any help!
