JS 省市县三级联动

     $(".area").change(function(ent,arg){
            var $this = $(this),
                 level = $(this).attr("id");
            $.ajax({
                url:'/Order/selectAddress',
                data:{l:level,type:'ajax',id:$this.val()|arg},
                success:function(ret){
                    var data = eval("("+ret+")"),
                        $subArea = $("#"+(parseInt(level)+1));
                        _html='<option value="" >请选择</option>';

                    for(var i in data){
                        _html += '<option value="'+data[i].region_id+'">'+data[i].region_name+'</option>';
                    }

                    $subArea.empty().append(_html);
                    $("#"+(parseInt(level)+2)).empty().append(_html);

                    if( 2 == $subArea.children().length ){
                        var _id = $subArea.children().eq(1).val();
                        $subArea.children().eq(1).attr("selected","true");
                        $subArea.val(_id);
                        $subArea.trigger("change",[_id]);
                    }
                }
            });
      });