dojo.hash throws exceptions in IE6 and IE7 if the server becomes unreachable

[Rob Retchless]

The hidden iframe fetches blank.html from the server. If the server goes down for any reason, the iframe shows "page cannot be reached", which is not on the same domain as the outer page, causing "Permission Denied" when the polling logic tries to read the iframe query string.

The fix: try catch a dummy read of the iframe query string and do error avoidance if an exception is caught. In this case, dojo.hash should still notify subscribers of hash changes when they happen, but don't add a back history entry and log an error. This will give subscribers a chance to react to the hashchange, and to show their own connection error messages.

[Adam Peller]

Patch from Rob Retchless (IBM, CCLA)

[Adam Peller]

(In [20643]) Check for exceptions if connection fails in IE. Patch from retchless. Fixes #10176 !strict

[kylehayes]

I'm still seeing this issue in 1.6

[bill]

Given the decline of IE6, probably this won't be fixed.