<script type="text/javascript">
function factory() {
/* 最顶级下拉框 */
var select = document.getElementById("factory");
var c = select.value;
/* 中级下拉框 */
var stand = document.getElementById("stand");
/* 最底层下拉框*/
var working = document.getElementById("working");
switch (c) {
/*当选中最顶级下拉框内容后,中级下拉框和最底级下拉框内容改变*/
/* 延安宝塔采油厂 */
case "yabtcyc":
stand.innerHTML = "<option>宝塔作业区</option>";
working.innerHTML = "<option>贾74(5从)</option>";
break;
/* 西北油田 */
case "xbyt":
stand.innerHTML = "<option>采气一厂</option>";
working.innerHTML = "<option>TK124(1丛)</option>";
break;
/* 第八采油厂 */
case "dbcyc":
stand.innerHTML = "<option>吴定作业区</option>";
working.innerHTML = "<option>新79-71(2丛)</option><option>新75-55(4丛)</option><option>元221(1丛)</option>";
break;
/* 测试厂 */
case "csc":
stand.innerHTML = "<option>测试作业区</option>";
working.innerHTML = "<option>测试井场(1丛)</option><option>测试井场2(1丛)</option><option>测试井场1(1丛)</option>";
break;
/* 延安杏子川采油厂 */
case "yaxzc":
stand.innerHTML = "<option>杏子川作业区</option>";
working.innerHTML = "<option>化旧301(null丛)</option>";
break;
default:
alert("error");
}
};
</script>
</head>
<body>
<div class="div">
<select id="factory" onchange="factory()">
<option value="yabtcyc">延安宝塔采油厂</option>
<option value="xbyt">西北油田</option>
<option value="dbcyc">第八采油厂</option>
<option value="csc">测试厂</option>
<option value="yaxzc">延安杏子川采油厂</option>
</select> <select id="stand">
<option value="宝塔作业区">宝塔作业区</option>
</select> <select id="working">
<option value="贾74(5从)">贾74(5从)</option>
<option value=""></option>
<option value=""></option>
</select>
</div>
</body>