[Bug] Cannot highlight cross-domain iframe

[yiminzme]

For example, in this example, when searching "python" in Multi Highlight, we expect both "python" in the webpage to be highlighted. But it is not the case.

I think it is because Multi Highlight currently doesn't work with the iframe HTML element. The red box highlight the location of iframe, and text in it doesn't seem to be searchable.

[yiminzme]

duplicate #41

[yiminzme]

One more website that doesn't work (can be used for testing)
https://docs.oracle.com/javase/8/docs/api/