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]);
}
}
});
});