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>