This question comes after two days of testing and debugging, right after the shock I had seeing that none of the websites i build using ajax-based login work in IE<8

The most simplified scenario si this:

1. mypage.php :

session_start();
$_SESSION['mytest'] = 'x';

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js">           
    </script>

    <script type="text/javascript">     
        function loadit() {
            $.post('http://www.mysite.com/myajax.php', {action: 'test'}, function(result){alert(result);}, 'html');
        }
    </script>


    <a href="javascript:void(0);" onclick="loadit(); return false;">test link</a>

2. myajax.php

session_start();
print_r($_SESSION);
print session_id();

When I click the "test link", the ajax call is made and the result is alert()-ed:

IE6:

weird bullet-character (•)

IE7:

Array(
)
<session_id>

IE8/FF (Expected behaviour):

Array(
    [mytest] => 'x'
)
<session_id>

I would really appreciate some pointers regarding: 1. why this happens 2. how to fix it

Thank you.