<form name=form1 action="123.asp" method=post>
<select onchange='form1.submit()'>
<option value=banana>banana
<option value=orange>orange
</select>
<input type=text>
</form>
<select onchange='form1.submit()'>
<option value=banana>banana
<option value=orange>orange
</select>
<input type=text>
</form>
<option value="http://www.csdn.net">csdn</option>
<option value="http://www.5aaa.com">北科网</option>
<option value="http://www.sina.com.cn">新浪</option>
</select>
<!--
function goSubmit() {
document.form1.submit();
}
-->
</script><select name="a" onchange="javascript:goSubmit()">
<option>...</option>
</select>