Jquery using make change in stylesheet

 <script type="text/JavaScript" src="../jquery.min.js"></script>

    <script type="text/JavaScript" src="../jquery-1.4.2.min.js"></script>

    <script type="text/JavaScript">  
$(document).ready(function(){
$('tr').mouseover(function() {
$(this).addClass('zebraHover');
});
$('tr').mouseout(function() {
$(this).removeClass('zebraHover');
});
$("#div1").css({'border':'1px solid red','font-size':'12px','font-weight':'bold'});
$("#div1").height();
$("#div1").height(120);
$("#div1").width();
$("#div1").width(200);

//alert(getyear());
});

    </script>

    <style type="text/css">
        tr.zebraHover
        {
            background-color: #BEBEBE;
        }
    </style>

 <table>
        <tr>
            <td id="celebs">
                Dhaval patel
            </td>
        </tr>
        <tr>
            <td>
                <div id="div1">
                    hi<br />
                    hello!<br />
                    How Are you?
                </div>
            </td>
        </tr>
    </table>