This bug isn't showing the usual generated source but some kind of hybrid between original source and generated source.

- To see the original source, hit ctrl-u before dismissing the alert.

- To see the "hybrid" source, hit ctrl-u after dismissing the alert. I always expected this to be idential to what the webserver sent, just syntax highlighted. (Though I haven't messed around with document.close before.)

- To see the generated source, hit ctrl-a, right click & "View Selection Source". This is different to the original/hybrid source as Firefox inserts html tags to make the page valid. My example had no html, head, title or body tags. This should reflect the current page DOM, as affected by any JavaScript.