The error appears in Web Inspector and no corresponding HTTP request appears in the web server logs. I stepped through the execution in Safari 5.0.3, and the click handler is triggered.
This is a significant issue that impacts major apps like Google Analytics. The only workaround appears to be setting the anchor's target attribute so that the page loads in a new window, e.g., target="_blank". Opening a new window disrupts the user experience and is frowned upon.
- Safari 4 Event Tracking on a Download and External Links Not Working
-__utm.gif Failed to load resource in Webkit when tracking clicks with Event Listeners
Editorial note: this could be a duplicate of bug:25359 but that bug is light on details; also, the symptoms are similar to to bug:46491 but is triggered differently.
Created attachment 83037 [details]
Did you test with nightly builds from <http://nightly.webkit.org>? I think that some of these ping mechanisms should work now.
Created attachment 83075 [details]
Another example with beforeUnload handler
Added a beforeUnload handler to the example to introduce a delay, in case the ping request was being interrupted by the default action due to some timing issue.
The only difference with the latest nightly (r78800) is that Web Inspector went from:
Failed to load resource.
GET http://url-of-ping-request undefined (undefined)
Created attachment 83076 [details]
Updated example with beforeunload handler.
Please re-open if this is still an issue in nightly builds.