IE adding a attribute 'done[number]'?

Hi all im struggling to find an answer to my problem here. I've made a IM application the same as facebooks but it is having problems in IE.

The problem started as I kept seeing rn at the beginnning of every post made via IE. That was due to stripslashes function. But as I was investigating I noticed my tag was being added an attribut 'done';

<li><UL done67="7">rn<LI class=name>ACTwebDesigns</LI>rn<LI class=speech>hello</LI></UL></li>
<li><UL done1="4">rn<LI class=name>ACTwebDesigns</LI>rn<LI class=speech>foo</LI></UL></li>
<li><UL done84="10">rn<LI class=name>ACTwebDesigns</LI>rn<LI class=speech>barr</LI>rn<LI class=speech ?>foobar</LI></UL></li>
<li><UL done88="14">rn<LI class=name>ACTwebDesigns</LI>rn<LI class=speech>this is a test</LI></UL></li>

does anyone know of a reason why IE would add this attribute?

EDIT:

    function checkForm() {
    $(".chat_input").keydown(function(e){
        if ( e.keyCode == 13 ) {
            var data = strip_tags($(this).val());
            var username = $("#users_username").val();
            var box = $(this).parents('div:eq(0)');
            $(this).val("");

            if( box.find('.conversation_box li.' + session_number ).length == 0 ) {
                var conversation_list = box.find('.conversation_box').html();
                var insert_data = '<li class="' + session_number + '"><ul><li class="name">' + username + '</li><li class="speech">' + data + '</li></ul></li>';
                box.find('.conversation_box').html(conversation_list + insert_data);
                bottom();
            }else{
                var conversation_list = box.find('.conversation_box li.' + session_number + ' ul').html();
                var insert_data = '<li class="speech"">' + data + '</li>';
                box.find('.conversation_box li.' + session_number + ' ul').html(conversation_list + insert_data);
                bottom();
            }
            return false;   
        }
    });
}

    function store_chat(){
    try{
        var token = $("#token").val();
        var openedBoxes = $("li.conversation_list");
        openedBoxes.each(function(){
            var boxContainer = $(this).parents('div:eq(0)');
            var amount = boxContainer.find('.conversation_box li').length;
            var p = boxContainer.find('.open_trigger').html();
            var u = $("#users_username").val();
            if( amount != 0 ){
                if( $(this).parents('div:eq(0)').find('.conversation_box li.' + session_number ).length != 0 ) {
                    var session_contents = $(this).parents('div:eq(0)').find('.conversation_box li.' + session_number ).html();
                    alert( session_contents );
                    $.ajax({ 
                        type: 'POST', url: './', data: 'token=' + token + '&re=7&s=' + amount + '&sd=' + sessi开发者_开发技巧on_contents + '&u=' + u + '&p=' + p, cache: false, timeout: 5000,
                        success: function(html){ 
                            auth(html); 
                            boxContainer.find('.conversation_box').html(html); 
                            bottom();
                        }                           
                    });
                }
            }
        });
    }catch(er){}
}

IE definitely won't do that automatically. Chances are it's some erd party script adding the attribute to keep track of some data against the node.