jsp,js问题

我的jsp代码如下：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><HTML>
<HEAD>
<%@ page 
language="java"
import="java.sql.*"
contentType="text/html; charset=GBK"
pageEncoding="GBK"
%>
<META http-equiv="Content-Type" content="text/html; charset=GBK">
<META name="GENERATOR" content="IBM WebSphere Studio">
<TITLE>TestCombox.jsp</TITLE>
<SCRIPT LANGUAGE="javascript" type="text/javascript" >
<!--
   var branch = new Array();
   var branchname = new Array();
   var aracde  = new Array();
   var aracdename = new Array();
   var bm = "",name = "";
   var i = 0 ;
   <%
      yxquery.YXDBConn DBConn = new yxquery.YXDBConn();
      Connection conn = DBConn.getConnection();
      Statement stmt = conn.createStatement();
      ResultSet rs = null;
      String branch ="";
      String branchname="";
      String sql ="";
      sql = "select branch,branch_name from ipe_branch order by branch";
      rs = stmt.executeQuery(sql);
      while (rs.next() ){
          branch =rs.getString("branch");
          branchname = rs.getString("branch_name").trim() ;
    %>
        bm = <%=branch%>;
        name = <%=branchname%>;
        branch[i] = bm;
        branchname[i] = name; 
        i = i+1;
    <%  }
      stmt.close();
      conn.close();
   %>
   
   function changeoption(form)
   {
        var x;
        var branchEle,aracdeEle ;
        for (var q=form.branch.options.length;q>=0;q--){               
            form.branch.options[q]=null;            
        }   
        for (var q=form.aracde.options.length;q>=0;q--){               
            form.aracde.options[q]=null;            
        }    
        
               
        for ( x = 0 ; x < branch.length  ; x++ )
        {                 
             branchEle = document.createElement("option") ;
             branchEle.value = branch[x] ;                  
             branchEle.text = branch[x];//branchname[x] ;                 
             form.branch.add(branchEle) ;                     
         }
         form.branch.selectedIndex = 0;
              
   }
//-->
</SCRIPT>
</HEAD>
<BODY onload="changeoption(form1)">
<FORM name="form1">
   <SELECT name="branch" >
   </SELECT>
   <SELECT name="aracde" >
   </SELECT>
</FORM>
</BODY>
</HTML>开发工具为：wsad，数据库为：DB2运行时执行到bm = <%=branch%>;或name = <%=branchname%>;报字符未定义，当bm为数字时是可以的，但为字母加数字时报字符未定义，当name为中文时就报字符未定义