<select id="test" style="display:none;width:90" width=80 >
<option>a</option>
<option>a</option>
</select><SCRIPT LANGUAGE="JavaScript">
<!--
alert(document.all.test.style.width);
alert(document.all.test.width);
//-->
</SCRIPT>//这个事先指定了宽
<option>a</option>
<option>a</option>
</select><SCRIPT LANGUAGE="JavaScript">
<!--
alert(document.all.test.style.width);
alert(document.all.test.width);
//-->
</SCRIPT>//这个事先指定了宽
改用visibility=hidden 可以用以下的方法取到宽高
<body onLoad="alert(test.offsetWidth+"\n"+test.offsetHeight);">
<select id="test" style="visibility: hidden">
<option>a</option>
<option>a</option>
</select>
</body>