One of my customers asked me how to mitigate this IE8's application compatibility issue.
Well, when their application tries to execute this code, it failes with 'invalide argument' error:
document.domain = somevalue;
Their web application works perfectly on IE6 and now they are considering moving to IE8.
Do you know why this fails?
This is explained in IE team blog as follows:
In Internet Explorer 7, the following set of calls would succeed: // initial document.domain is app1.example.com document.domain = "app1.example.com"; // 1. Domain property set to default value document.domain = "example.com"; // 2. “Loosen” domain document.domain = "app1.example.com"; // 3. “Tighten” domain In Internet Explorer 8 and other browsers, the 3rd assignment will throw an exception, because app1.example.com is not a suffix of the then-current value, example.com.
In Internet Explorer 7, the following set of calls would succeed:
// initial document.domain is app1.example.com document.domain = "app1.example.com"; // 1. Domain property set to default value document.domain = "example.com"; // 2. “Loosen” domain document.domain = "app1.example.com"; // 3. “Tighten” domain
In Internet Explorer 8 and other browsers, the 3rd assignment will throw an exception, because app1.example.com is not a suffix of the then-current value, example.com.
http://blogs.msdn.com/ie/archive/2008/09/02/ie8-security-part-vi-beta-2-update.aspx
In this case, I think the developer who understands the application needs to find how to mitigate this issue, considering using postMessage() or XDomainRequest.