The drupalchat-min.js have a bug in IE cache.

My solution:

--- drupalchat-min.js	(6.x-2.0-beta4 )
+++ drupalchat-min.js	(6.x-2.0-beta4 )

- <param name=\"movie\" value=\""+Drupal.settings.drupalchat.sound+"\"/>
+ <param name=\"movie\" value=\""+Drupal.settings.drupalchat.sound+"?random="+(Math.random()+new Date().getMilliseconds())+"\"/>


or:
- <param name=\"movie\" value=\""+Drupal.settings.drupalchat.sound+"\"/>
+ <param name=\"movie\" value=\""+Drupal.settings.drupalchat.sound+"?random="+new Date().getTime()+"\"/>

I try the 6.x-2.0-beta5,
But I have the error(in ie8):

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Timestamp: Wed, 14 Sep 2011 11:03:11 UTC

Message: Object doesn't support this property or method
Line: 243
Char: 6
Code: 0
URI: http://localhost/sites/all/modules/drupalchat/js/drupalchat.js?X

I clear the IE cache again and again, but there has always been the error.
You'll have the error when you receive the message, but you don't have the error when you don't have message.

I clear my IE cache once and try again. It's OK, but....

If the page is being refreshed or is being loaded other page, you will receive the error in IE.
If you logged out and then logged in, you will receive the error in IE.
You’ve been keeping to clear the IE cache................

BTW, on another machine I always receive the error,even though I clear the IE cache again and again. The Drupalchat don't work.

I try the 6.x-2.0-beta6,
But I have the error(in ie8):

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET CLR 2.0.50727)
Timestamp: Fri, 16 Sep 2011 09:45:25 UTC

Message: '0.scrollHeight' Null or not an object
Line: 64
Char: 12
Code: 0
URI: http://localhost/sites/all/modules/drupalchat/js/drupalchat.js?j

But soon I discovered that the error caused by disabling the Long Polling in admin/settings/drupalchat or not opening the subpanel. So minor changes can help make code more robust and easier to use.

in 6.x-2.0-beta6:
I find that the same message always will be displayed again and again, never stopping . See the attachment.

I try the 6.x-2.0-beta7. It's OK. Thank you!

BTW, The blocking issues in IE continue to exist. If you click the links on the page you will find the IE is getting slow(More than two clicks). See here: http://drupal.org/node/1276674

The error repeating the same message continue to exist, but sometimes It's ok.
I don't know what is wrong with it.

I tested the Drupalchat 6.x-2.0-beta8 in localhost and intranet again.
1. In localhost it's OK in IE8.
2. in intranet computer A, it's OK in IE8 too.
3. But in intranet computer B, an error occurs again in ie8.

Message: Object doesn't support this property or method
Line: 246
Char: 6
Code: 0
URI: http://localhost/sites/all/modules/drupalchat/js/drupalchat.js?X

So I comment out the obj.drupalchatbeep(), and the computer B works in IE8.

 if (obj) {
     //obj.drupalchatbeep(); // e.g. an external interface call
  }

I can't work out what was going wrong, so I google and find that blow.

     swfobject.registerObject("myCom", "9.0.0", "expressInstall.swf", callbackFn);
     function callbackFn(status) {
            if (status.success) {
                var obj = status.ref;
                document.getElementById("but1").onclick = function() {
                    if (obj && typeof obj.JStoASviaExternalInterface != "undefined") {
                        obj.JStoASviaExternalInterface(document.getElementById("send").value);
                    }
                };
      .......

But I don't know how to do. It's just a simple indication.

Hi.

The error appear again in intranet computer C (in IE7).
Message: Object doesn't support this property or method
Line: 247
Char: 6
Code: 0
URI: http://168.192.1.1/sites/all/modules/drupalchat/js/drupalchat.js?X

I comment out the obj.drupalchatbeep(), and the computer C works.

No, The error appear in IE7 and IE8 sometimes, but some machine don't appear sometimes.

Today, I test the Drupalchat 6.x-2.0-beta8 again.

I test 4 computer across the intranet with IE.
In localhost , Everything is all right. It's browser version is IE8(8.0.6001.18702).
In intranet, computer A is all right. It's browser version is IE8(8.0.6001.18702).
In intranet, computer B don't work. It's browser version is IE8(8.0.6001.18702).
In intranet, computer C don't work. It's browser version is IE7.
BTW: if using the Firefox, all computer work !

The error is caused by obj.drupalchatbeep().
So I comment out the obj.drupalchatbeep(), and all computer work !