<form name="frmS" action="#">
<p>プルダウンのサイズ変更:
<label for="sz5"><input type="radio" id="sz5" name="sz" value="5" onclick="fSetSelectSize(this.value)" />5</label>
<label for="sz4"><input type="radio" id="sz4" name="sz" value="4" onclick="fSetSelectSize(this.value)" />4</label>
<label for="sz3"><input type="radio" id="sz3" name="sz" value="3" onclick="fSetSelectSize(this.value)" />3</label>
<label for="sz2"><input type="radio" id="sz2" name="sz" value="2" onclick="fSetSelectSize(this.value)" />2</label>
<label for="sz1"><input type="radio" id="sz1" name="sz" value="1" onclick="fSetSelectSize(this.value)" />1(デフォルト)</label>
</p>
<p>
<select name="selS">
<option value="0">-----------</option>
<option value="1">アイテム1</option>
<option value="2">アイテム2</option>
<option value="3">アイテム3</option>
<option value="3">アイテム4</option>
<option value="3">アイテム5</option>
</select>
</p>
</form>
<script type="text/javascript">
function fSetSelectSize(num){
var sObj=document.forms["frmS"].elements["selS"];
sObj.size=num;
}
</script>