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。