Example of onchange event usage of select in jsp

<script language = "JavaScript"> 
 var onecount; 
 onecount=0; 
 subcat = new Array(); 
 <% 
 int count = 0; 
  rs1 = ("select hydm,zhydm,zhymc from zhy ");//Read data while(()) 
 { 
 String selhydm=("hydm").trim(); 
 String zhydm=("zhydm").trim(); 
 String zhymc=("zhymc").trim(); 
 %> 
 subcat[<%=count%>] = new Array("<%=zhydm%>","<%=selhydm%>","<%=zhymc%>");//Produce an array <% 
 count = count + 1; 
 } 
 if(rs1!=null) (); 
 %> 
 onecount=<%=count%>; 
 function changelocation(id) 
 { 
 document. = 0; 
 var hydm=id; 
 var i; 
 document.[0] = new Option('Choose a sub-industry category',''); 
 for (i=0;i < onecount; i++) 
 { 
 if (subcat[i][1] == hydm) 
 { 
 document.[document.] = 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">Select industry classification:</td> 
 <td width="320"> 
 <select name="selhy" onChange="changelocation(document.[document.].value)" size="1" > 
 <option value="2">请Select industry classification</option> 
 <% 
 rs = ("select * from hy"); 
 while(()) 
 { 
  String hydm=("hydm").trim(); 
  String hymc=("hymc").trim(); 
 %> 
 <option value="<%=hydm%>"><%=hymc%></option> 
 <% 
 } 
 if(rs!=null) (); 
 %> 
 </select> 
 </td> 
 </tr> 
 <tr> 
 <td height="20" align="right">Select sub-industry classification:</td> 
 <td> 
 <select name="selzhy" > 
 <option value="" selected>请Select sub-industry classification</option> 
 </select> 
 </td> 
 </tr> 
</table>

<form name=form1> 
 <select name=province onchange="cityName()"> 
  <option value="">Please select the provincial name</option> 
 </select> 
 <select name=city> 
  <option value="">Please select the city name</option> 
 </select> 
 </form> 
 
 <script language=javascript> 
 var city1 = ["Hangzhou", "Ningbo", "Wenzhou", "Shaoxing", "Jinhua", "Huzhou"]; 
 var city2 = ["Nanjing", "Suzhou", "Wuxi", "Changzhou", "Zhenjiang", "Xuzhou"]; 
 var city3 = ["Hefei", "Xi County", "Huangshan", "Qimen", "Xuening"]; 
 var city4 = ["Nanchang", "Jiujiang", "Ganzhou", "Shangrao", "Xinyu", "Jingdezhen"];  
 var provinceName = ["Zhejiang", "Jiangsu", "Anhui", "Jiangxi"]; 
 function province() 
 { 
   var e = document.; 
   for (var i=0; i<; i++) 
    (new Option(provinceName[i], provinceName[i])); 
 } 
 function cityName(n) 
 { 
   var e = document.; 
   for (var i=; i>0; i--)  (i); 
   if (n == 0) return; 
   var a = eval("city"+ n); //Get the array name of the city   for (var i=0; i<; i++) (new Option(a[i], a[i])); 
 } 
 function () 
 { 
   province(); //At the initial content to the drop-down menu for the name of the province } 
 </script>