셀렉트박스(SelectBox) 마우스오버시 크기 늘리기

<style type="text/css">
<!--
.selectid {
    width: 60px;
    m: expression(this.onmouseover =  new Function("this.className = 'ie';"));
}
.selectid:hover {
    width: 500px;
    position: absolute;
}
.ieout {
    position: absolute;
    width: 500px;
    m: expression(this.onclick=  new Function("this.className = 'selectid';"));
}
.ie {
    position: absolute;
    width: 500px;
    m: expression(this.onclick=  new Function("this.className = 'ieout';"));
}
-->
</style>

2. body 기입
<select class="selectid" >
<option>aaaaaaaaaaaaaaaaaaaaaaaaaaaaa</option>
<option>bbbbbbbbbbbbbbbbbbbbbbbbbbbbb</option>
<option>ccccccccccccccccccccccccccccc</option>
</select>