基于Javascript实现二级联动菜单效果

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
效果图如下：

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。