本文实例为大家分享了Javascript实现二级联动菜单效果的对应代码，具体内容如下
具体实现步骤如下：
1.所用js代码如下：
<script type="text/javascript">
var arr_province=["请选择省份/城市","北京市","上海市","天津市","河南省","山东省","河北省"];
var arr_city=[
["请选择城市/地区"],
["中关村","海淀区","朝阳区","昌平区","丰台区","大兴区"],
["宝坻区","浦东新区","长宁区","徐汇区","虹口区","宝山区"],
["和平区","河东区","河西区","塘沽区","大港区","北辰区"],
["郑州市","洛阳市","商丘市","开封市","安阳市","濮阳市"],
["济南市","青岛市","烟台市","德州市"],
["石家庄","菏泽市","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";
//给province赋值高度，才能在其里面写入内容
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];
}
//设置默认被选中的选项
var index=0;
province.selectedIndex=index;
//给city赋值高度，才能在其里面写入内容
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中的代码如下：
<body onload="init()">
<form name="form1">
所在地区：<select name="province" onchange="select_change(this.selectedIndex)"></select>
城市：<select name="city"></select>
</form>
</body>
第二个效果：
1.利用javascript来实现鼠标经过图片放大，鼠标移出图片恢复的效果，具体代码如下：
<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中的代码如下：
<body onload="init()">
<img id="img0" src="images/4.jpg" />
</body>
以上就是本文的全部内容，希望对大家学习javascript程序设计有所帮助。