下面这段代码什么意思

Question

 function save(){
            if($("#ID").val()==""){
            $("#ID").tips({
                side:3,
                msg:'请输入媒体类型ID',
                bg:'#AE81FF',
                time:2
            });
            $("#ID").focus();
            return false;
            }

            if($("#ID").val()){
                var flag=validateID($("#ID").val())
                if(flag){
                    freshID();
                }
            }
            function validateID(id){
            $.ajax({
                url:'validate_id',
                data:{id:$("#ID").val()},
                dataType:'json',
                type:'post',
                success:function(resp){
                    return resp.msg
                }
            });
        }
        function freshID(){
            $.ajax({
                url:'fresh_id',
                dataType:'json',
                type:'post',
                success:function(resp){
                        $("#ID").val(resp.ID)
                }
            });

controller中代码
            /**
     * 保存前校验
     * @param sitecode
     * @return
     * @throws Exception
     */
    @RequestMapping(value="/validate_site_code")
    @ResponseBody
    public Object validateSiteCode(String sitecode) throws Exception {
        PageData pd = new PageData();       
        Map<String,Object> map = new HashMap<String,Object>();
        pd = this.getPageData();
        if (siteService.hasThisCode(sitecode)) {
            map.put("msg", "true");
        }else{
            map.put("msg", "false");
        }
        return AppUtil.returnObject(pd, map);
    }

    /**
     * 刷新站点代码
     * @return
     * @throws Exception
     */
    @RequestMapping(value="/fresh_site_code")
    @ResponseBody
    public Object freshSiteCode() throws Exception {
        PageData pd = new PageData();       
        Map<String,Object> map = new HashMap<String,Object>();
        pd = this.getPageData();
        map.put("SITE_CODE", getNextSiteCode());
        return AppUtil.returnObject(pd, map);
    }

Answer 1