rails jquery的二级联动

$(function(){   
   $("#area_parentID").change(function(){   
       $("#next_select").html("<select name='streat' id='streat'></select>");   
       $.post(    
       "/banks/select_with_ajax",   
       {"parentID":$("#area_parentID").val()},   
       function(data){   
          var datas = eval(data);   
      //alert(datas);   
      $.each(datas,function(i){   
              $("<option value='"+datas[i].area.id+"'>"+datas[i].area.name+"</option>").appendTo($("#streat"));   
          });          
       });   
   });   
});

 

<tr>  
<td>地域</td><td><%=    
  @areas = Area.find(:all, :select => 'name,id',:conditions=>"parentID=0").collect{|t| [t.name,t.id]}.insert(0,["请选择",0])          
  select("area","parentID",@areas,{},{:selected=>1})%><span id='next_select'><select name="streat" id="streat"></select></span></td>  
</tr> 

 

def select_with_ajax             
      @areas = Area.find(:all, :select => "name,id",:conditions => ["parentID = ?", params[:parentID]])                 
      render(:json => @areas.to_json,:layout => false)   
  end