Called before form submits request to save record. This event is triggered before save request is sent to the server to save record data. If you want to add an event after data is returned, see .onSave event. These two events are called when user clicks the save button. You can add event listener during the object creation: let form = new w2form({ name : 'form', url : 'server/post', record: { field_1 : 1, field_2 : 2 }, fields: [ { field: 'field_1', type: 'text', required: true }, { field: 'field_2', type: 'alphanumeric', required: true } ], onSubmit: function(event) { console.log(event); } }); or after the object has been created: w2ui.form.on('submit', function(event) { console.log(event); }); The event handler is called before the default action of the event is triggered. You can cancel the default action by calling event.preventDefault(). To perform an action after the event is fully processed, define event.onComplete function. See events page in utilities for more details.