变换的下拉选择菜单

- 中国WEB开发者网络 (http://www.webasp.net)
-- 网页特效 (http://www.webasp.net/javascript/)
--- 变换的下拉选择菜单 (http://www.webasp.net/javascript/1/744.htm)
-- 发布日期： 2005-07-04
<!-- 网页特效代码由[中国WEB开发者网络:http://www.ChinaWebDev.com]提供！ -->
<!-- 要实现此效果需要 1 个步骤： -->

<!-- 第 1 步： -->
<!-- 把下面的代码加到<BODY></BODY>区域中： -->

<style>
#sub1, #sub2, #sub3
{ position: absolute;
left: 480px;
visibility: hidden;
z-index: 3
}
</style>

<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
catnumber = 3
offset = 150
performOnchange = false
if (document.all) {
docObj = "document.all."
styleObj = ".style"
} else {
docObj = "document."
styleObj = ""
}
function openselect(subcat) {
popupselect = eval(docObj + subcat + styleObj)
popupselect.visibility = "visible"
}
function closeselect(submenu,subcat){
popupselect = eval(docObj + subcat + styleObj)
if (submenu.selectedIndex != 0) {
popupselect.visibility = "hidden"
numchoice = submenu.selectedIndex
choice = submenu[numchoice].value
subcategory.value = choice
submenu.selectedIndex = 0
}
}
function lock() {
performOnchange = false
}
function unlock() {
performOnchange = true
}
function selectSub(cat) {
for (i=1; i <= catnumber; i++) {
subcat = "sub" + i
popupselect = eval(docObj + subcat + styleObj)
popupselect.visibility = "hidden"
}
if (performOnchange == true) {
letsopen = "sub" + cat.selectedIndex
if (letsopen == "sub0") {
alert("No category selected")
choice = "- subcategory -"
subcategory.value = choice
cat.focus()
} else {
openselect(letsopen)
lock()
}
}
}
// End -->
</script>
<div align="center">
<span id="sub1">
<select name="subannounce" onchange="closeselect(this,'sub1')">
<option selected value="">- 综合性站点 -
<option value="新浪网">新浪网
<option value="搜狐">搜狐
<option value="网易">网易
</select>
</span>
<span id="sub2">
<select name="subarts" onchange="closeselect(this,'sub2')">
<option selected value="">- 艺术性站点 -
<option value="chinamp3">chinamp3
<option value="通海微雕">通海微雕
<option value="painting">painting
</select>
</span>
<span id="sub3">
<select name="subsoftware" onchange="closeselect(this,'sub3')">
<option selected value="">- 体育类站点 -
<option value="中国足球网">中国足球网
<option value="中国篮球网">中国篮球网
<option value="NBA">NBA
<option value="新浪体育">新浪体育
</select>
</span>
<select name="categoria" onmouseover="unlock()" onchange="selectSub(this)">
<option selected value="">-- 选择站点类型 --
<option value="综合性站点">综合性站点
<option value="艺术性站点">艺术性站点
<option value="体育类站点">体育类站点
</select><br>
<input type="text" name="subcategory" readonly="readonly" value="- 选择具体站点 -">
</div>


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