在外部域上跨iFrame postMessage

Question

I've got multiple iFrames (same domain) on an external domain. If I do window.top.frames["name-here"].postMessage() and the frame exists, then obviously the postMessage executes correctly.

However, In this case the iFrames are modular based so they all do not need to exists. So if I init "window.top.frames["name-here"].postMessage("HI","*")" and that frame doesn't exists, it'll incur a Blocked a frame with origin "xyz" from accessing a cross-origin frame. I'm assuming this isn't a big deal since it won't throw any on page errors.

I've tried looping through the window.top.frames with postMessage, but that also throws a CORS error.

Answer 1

The error is probably not with the postMessage , but with the access to the frame itself. A call to window.top.frames["name-here"] will most likely give you the same message. As you say, I don't think the error is a big problem, but if you want to get rid of it, you can get frames length and send your messages accordingly. Like this:

var existing_frames = window.top.frames.length;