本文實例爲大家分享了Javascript實現二級聯動菜單效果的對應代碼，具體內容如下
效果圖如下：
具體實現步驟如下：
1.所用js代碼如下：
<script type="text/javascript">
var arr_province=["請選擇省份/城市","北京市","上海市","天津市","河南省","山東省","河北省"];
var arr_city=[
["請選擇城市/地區"],
["中關村","海淀區","朝陽區","昌平區","豐臺區","大興區"],
["寶坻區","浦東新區","長寧區","徐彙區","虹口區","寶山區"],
["和平區","河東區","河西區","塘沽區","大港區","北辰區"],
["鄭州市","洛陽市","商丘市","開封市","安陽市","濮陽市"],
["濟南市","青島市","煙臺市","德州市"],
["石家莊","菏澤市","唐山市"],
];
function init()
{
var province=document.form1.province;
province.style.width=150+"px";
var city=document.form1.city;
city.style.width=150+"px";
//給province賦值高度，才能在其裏面寫入內容
province.length=arr_province.length;
for(var i=0;i<arr_province.length;i++)
{
province.options[i].text=arr_province[i];
province.options[i].value=arr_province[i];
}
//設置默認被選中的選項
var index=0;
province.selectedIndex=index;
//給city賦值高度，才能在其裏面寫入內容
city.length=arr_city[index].length;
for(var j=0;j<arr_city[index].length;j++)
{
city.options[j].text=arr_city[index][j];
city.options[j].value=arr_city[index][j];
}
}
function select_change(num)
{
var city=document.form1.city;
city.length=0;
city.length=arr_city[num].length;
for(var i=0; i<arr_city[num].length;i++)
{
city.options[i].text=arr_city[num][i];
city.options[i].value=arr_city[num][i];
}
}
</script>2.body中的代碼如下：
<body onload="init()">
<form name="form1">
所在地區：<select name="province" onchange="select_change(this.selectedIndex)"></select>
城市：<select name="city"></select>
</form>
</body>第二個效果：
1.利用javascript來實現鼠標經過圖片放大，鼠標移出圖片恢復的效果，具體代碼如下：
<script type="text/javascript">
function init()
{
var img0=document.getElementById("img0");
img0.onmouseover=function()
{
img0.style.width=img0.offsetWidth*1.5+"px"
}
img0.onmouseout=function()
{
img0.style.width=img0.offsetWidth/1.5+"px"
}
}
</script>2.body中的代碼如下：
<body onload="init()">
<img id="img0" src="images/4.jpg" />
</body>