使用jquery或javascript获取多选框的值

<script>
    function val() {
        //Get values of mutliselect drop down Box
    }

    $(document).ready(function () {
        var flag = 0;
        $('#emp').change(function () {
            var sub = $("OPTION:selected",this).val()
            if (flag == 1) $('#new_row').remove();
            $('#topics').val('');
            var html = '<tr id="new_row" class="new_row"><td>Topics:</td><td>  <select    id="topic_l" name="topic_l" class="topic_l" multiple="multiple">';
            var idarr = new Array();
            var valarr = new Array(); { %
                for top in dict.tops %
            }
            idarr.push('{{top.is}}');
            valarr.push('{{pic.ele}}'); { % endfor %
            }
            for (var i = 0; i < idarr.length; i++) {
                if (sub == idarr[i]) {
                    html += '<option value="' + idarr[i] + '" >' + valarr[i] + '</option>';
                }
            }
            html += '</select></p></td></tr>';
            $('#tops').append(html);
            flag = 1;
        });
    });
</script>
Emp:&nbsp;&nbsp;&nbsp;&nbsp;
<select id="emp" name="emp">
    <option value=""></option>
    <option value="1">1</option>
</select>

<div name="tops" id="tops"></div>

<input type="submit" value="Create Template" id="create" onclick="javascript:var ret=val();return ret;">

谢谢..