Defines dateType for the form If dataType is not defined, the default one comes from w2utils.settings.dataType. This property can be set during object creation: let form = new w2form({ name: 'form', dataType: 'JSON', url: '/server/url', fields: [ { field: 'first_name', type: 'text', required: true }, { field: 'last_name', type: 'text', required: true }, { field: 'email', type: 'email' } ], actions: { "save": function () { this.validate(); }, "reset": function () { this.clear(); } }, }) Or any time during run-time: form.dataType = 'JSON';