jquery 操作select IE7下奇怪问题

在IE下，点击click me 按钮两次会出现下拉框不可选，不知为何，重新创建的select控件，第二次添加值会出问题。火狐下没有此问题

<script type="text/javascript" src="http://code.jquery.com/jquery-1.6.1.min.js"></script>
<SCRIPT type="text/javascript">
<!--
var add_i = 0;
$(function (){
    $("#btn").click(function (){
        if(add_i%2 == 0){
            if(window.console != undefined)console.log('create select');
            $("#box").empty().append('<p>'+add_i+'</p><select name="A" id="A"></select>');
        }
        var data = {"4249":"Manicaland","4250":"Mashonaland Central","4251":"Mashonaland East","4256":"Mashonaland West","4255":"Masvingo","4253":"Matabeleland North","4254":"Matabeleland South","4252":"Midlands"};
        var str = "<option value=''> Select State/Province </option>";
        for(i in data){
            str+= "<option value='" + i + "'>" + data[i] + "</option>";
        }
        $("#A").empty().append(str);
        add_i++;
    });
});
//-->
</SCRIPT>
<div id="box">
    <select name="A" id="A">
    </select>
</div>
<input type="button" value="click me" onclick="" id="btn">