backbone Model调用save方法的时候提交方式

horizon使用的是backbone框架，但是我们的后台api都是只接收post请求，请求的路径为/api/，根据backbone的官档解释：

backbone的model.save方法会判断当前的model对象是否存在存在服务器中，如果存在服务器中，则调用"update" (HTTP PUT), 如果不存在，则调用"create" (HTTP POST)， 判断的依据即为当前的model的属性'id'是否存在。

举例如下：

    var UpdateAgentV = ModalView.extend({
        initialize: function(data) {
            this.model = new UpdateAgentM();
            this.setDefault();
            this.defaults.id = 'edit-agent';
            this.defaults.header = translate('operations.edit');
            this.renderModal();

            this.model.bind('change', this.render, this);
            this.model.set({
                agents_id: data.project_id
            });
            this.getAgent(data.project_id);
        },
        getAgent: function(project_id){
            var $this = this;
            this.ajaxRequest({
                action: 'GetAgentsDetail',
                project_id: project_id
            }, function(res){
                $this.model.set({
                    account_bank: res.data.account_bank,
                    account_name: res.data.account_name,
                    account_number: res.data.account_number,
                    url: res.data.url,
                    logo: res.data.logo,
                    company: res.data.company,
                });
            });
        },
        render: function() {
            tpl = _.template($("#template-edit-agent").html());
            this.defaults.body =  tpl(this.model.toJSON());
            this.$el.html(this.template(this.defaults));
            $('.modal-dialog').draggable({ handle: "div.modal-header" });
            return this;
        },
    });
    var UpdateAgentM = ModalModel.extend({
        defaults: {
            action: 'UpdateAgents',
            agents_id: '',
            account_bank: '',
            account_name: '',
            account_number: '',
            url: '',
            logo: '',
            company: '',
        },
        initialize: function() {
            this.validator();
        },
        validator: function() {
            $("#edit-agent").find("form").validate({
                rules: {
                    account_bank: {
                        required: true
                    },
                    account_name: {
                        required: true
                    },
                    account_number: {
                        required: true
                    },
                    url: {
                        required: true
                    },
                    logo: {
                        required: true
                    },
                    company: {
                        required: true
                    },
                }
            });
        },
        create: function(element) {
            var data = this.formSerialize(element);
            this.set(data);
            this.saved(agentsView);
        }
    });

上例中若将UpdateAgentV的initialize的this.model.set({agents_id: data.project_id});改为this.model.set({id: data.project_id});， 则在model调用save方法时则会认为当前的model已经存在，提交数据就会用PUT方法。