oracle 中SID 代表什么意思？？

 你有几个问题： 
 
 1）select上没有ID，但你正在查询id（你也有一个不合适的“os”; <select name="os" os>无效） 
 
 2）您不是在寻找选择了哪个选项 
 
 要修复，请选择一个id ： 
 
<select name="os" id="os">
    <option value="1">Windows XP 32-bit</option>
    <option value="2">Windows XP 64-bit</option>
    <option value="3">Windows Vista 32-bit</option>
    <option value="4">Windows Vista 64-bit</option>
    <option value="5">Windows 7 32-bit</option>
    <option value="6">Windows 7 64-bit</option>
    <option value="7">Server 2003 32-bit</option>
    <option value="8">Server 2003 64-bit</option>
    <option value="9">Server 2008 32-bit</option>
    <option value="10">Server 2008 64-bit</option>
    <option value="11">Linux</option>
</select>
 
 并从jQuery查询： 
 
var osval = $('#os option:selected')
 
 或者，按名称查询： 
 
var osval = $('[name="os"] option:selected')
 
 http://jsfiddle.net/5Vmxd/ 

You have a couple of problems:
 
1) There is no ID on the select, yet you are querying for the id (you have an out-of-place "os" in there too; <select name="os" os> is not valid)
 
2) You aren't looking for which option has been selected
 
To fix, give the select an id:
 
<select name="os" id="os">
    <option value="1">Windows XP 32-bit</option>
    <option value="2">Windows XP 64-bit</option>
    <option value="3">Windows Vista 32-bit</option>
    <option value="4">Windows Vista 64-bit</option>
    <option value="5">Windows 7 32-bit</option>
    <option value="6">Windows 7 64-bit</option>
    <option value="7">Server 2003 32-bit</option>
    <option value="8">Server 2003 64-bit</option>
    <option value="9">Server 2008 32-bit</option>
    <option value="10">Server 2008 64-bit</option>
    <option value="11">Linux</option>
</select>
 
and query that from jQuery:
 
var osval = $('#os option:selected')
 
or, query by name:
 
var osval = $('[name="os"] option:selected')
 
http://jsfiddle.net/5Vmxd/