Overlay showing WiFi coverage is missing. Works fine with Tiger WebKit.
Are you sure this has nothing to do with the JS exceptions showing up in the console?
I didn't notice those. Could well be.
A major problem here is that the page has a comment as the first child of html :
Google maps script does document.documentElement.firstChild and expects to find the head. This works in Firefox as it reparents all comments before body to head but fails in ToT where the comment is kept as a child of html.
Fixing this gets rid of exceptions and makes the overlay work when clicking enable/disable button. There is some other problem besides this as the overlay still does not show up on first page load.
Created attachment 15481 [details]
test case for comment problem
WebKit behavior here does match the current HTML5 draft parsing rules though it does not match either Firefox or IE.
<rdar://problem/5344233> is tracking this as an Evangelism problem that Google is aware of.
Fixed by Google.