jsp中select的onchange事件用法实例

<script language = "JavaScript">  var onecount;  onecount=0;  subcat = new Array();  <%  int count = 0;  java.sql.ResultSet rs1 = DBManage.executeQuery("select hydm,zhydm,zhymc from zhy ");//读取数据  while(rs1.next())  {  String selhydm=rs1.getString("hydm").trim();  String zhydm=rs1.getString("zhydm").trim();  String zhymc=rs1.getString("zhymc").trim();  %>  subcat[<%=count%>] = new Array("<%=zhydm%>","<%=selhydm%>","<%=zhymc%>");//产生数组  <%  count = count + 1;  }  if(rs1!=null) DBManage.closeCOnn();  %>  onecount=<%=count%>;  function changelocation(id)  {  document.form1.selzhy.length = 0;  var hydm=id;  var i;  document.form1.selzhy.options[0] = new Option('选择子行业分类','');  for (i=0;i < onecount; i++)  {  if (subcat[i][1] == hydm)  {  document.form1.selzhy.options[document.form1.selzhy.length] = new Option(subcat[i][2], subcat[i][0]);  }    }  } </script> <table width="500" border="0" cellspacing="0" cellpadding="0" align="center">  <tr>  <td width="180" height="20" align="right">选择行业分类:</td>  <td width="320">  <select name="selhy" onChange="changelocation(document.form1.selhy.options[document.form1.selhy.selectedIndex].value)" size="1" >  <option value="2">请选择行业分类</option>  <%  rs = DBManage.executeQuery("select * from hy");  while(rs.next())  {   String hydm=rs.getString("hydm").trim();   String hymc=rs.getString("hymc").trim();  %>  <option value="<%=hydm%>"><%=hymc%></option>  <%  }  if(rs!=null) DBManage.closeCOnn();  %>  </select>  </td>  </tr>  <tr>  <td height="20" align="right">选择子行业分类:</td>  <td>  <select name="selzhy" >  <option value="" selected>请选择子行业分类</option>  </select>  </td>  </tr> </table><form name=form1>  <select name=province onchange="cityName(this.selectedIndex)">   <option value="">请选择省名</option>  </select>  <select name=city>   <option value="">请选择城名</option>  </select>  </form>   <script language=javascript>  var city1 = ["杭州", "宁波", "温州", "绍兴", "金华", "湖州"];  var city2 = ["南京", "苏州", "无锡", "常州", "镇江", "徐州"];  var city3 = ["合肥", "翕县", "黄山", "祁门", "休宁"];  var city4 = ["南昌", "九江", "赣州", "上饶", "新余", "景德镇"];   var provinceName = ["浙江", "江苏", "安徽", "江西"];  function province()  {    var e = document.form1.province;    for (var i=0; i<provinceName.length; i++)     e.options.add(new Option(provinceName[i], provinceName[i]));  }  function cityName(n)  {    var e = document.form1.city;    for (var i=e.options.length; i>0; i--)  e.remove(i);    if (n == 0) return;    var a = eval("city"+ n); //得到城市的数组名    for (var i=0; i<a.length; i++) e.options.add(new Option(a[i], a[i]));  }  function window.onload()  {    province(); //初始时给省名下拉菜单赋内容  }  </script>