Sencha Inc. | HTML5 Apps

Form FAQ

Published Sep 17, 2010 | The Sencha Dev Team | FAQ | Medium
Last Updated Jul 11, 2011

This FAQ is most relevant to Ext JS, any version.

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Field labels are not displayed

A Field's labels are rendered by the FormLayout layout manager. The Container in which the Fields are located must be configured with layout: 'form'

What is the basic thing to keep in mind about forms?

  • A BasicForm is not a layout managing Container. It exists solely to manage a collection of Ext.form.Field objects. Those Fields need to be rendered.
  • You need to add Fields to an Ext.form.FormPanel which is a Container which manages child Components, rendering them and sizing them where configured.
  • A FormPanel owns a BasicForm which is used to perform submissions and loads.
  • In order to render Fields correctly with labels, the container they are in (no matter what kind of Panel it is) must have layout:'form'. This is because it is the layout manager that actually renders child items. Only the FormLayout class knows how to render form Fields with all their extra wrappings.

Using a JsonReader with a Form?

If using JSON as the transport, do not use a Reader in a Form. Forms understand JSON natively.

How can I hide form or checkbox fields and their labels?

  • Use textfield.hide on a TextField to hide only the textfield
  • Use checkbox.hide to hide only the checkbox.

Options to hide the label, semicolon and the TextField:

  • set the labelStyle:'display:none', or labelSeparator:' ' or ' '
  • apply a class
new Ext.form.TextField({
    fieldLabel: elem<i>.label,
    name: elem<i>.id,
    itemCls : 'invisible'
var f = form.findField('yourField');

How to do overall form validation at onSubmit

How are responses handled when using forms versus say ajax requests?

First of all, there is a difference between Ajax.request and Form.submit.

  • Ajax.request is more "raw" while Form.submit does more processing. Ajax.request calls success and failure functions with 2 arguments: response and options. response contains headers and other properties including responseText. responseText is raw text returned from server. You must decode it to an object and analyze.
    • Function failure is called if and only if there is a error communicating with server (e.g. page not found, timeout, etc.)
    • Here is an example of Ajax.request call, together with an error handler
var o = {
            ,success:function(response, options) {
                var o = {};
                try {o = Ext.decode(response.responseText);}
                catch(e) {
                if(true !== o.success) {
                    //error occurred, act accordingly
                else {
                    // do your success processing here
            ,failure:function(response, options) {
        }; // end of o setup

In the above: success:true, error:'msg' are arbitrary in this case. The code above is general in that it describes the logic.

  • Form.submits are handled differently.
    • success and failure functions are called with 2 arguments: form, action.
    • action.result contains already decoded json response from server and success is called only and only if server returns {"success":true}.
    • failure is called also if client validation fails and form is not submitted to the server at all in that case.

How can I hide form fields and their labels?

See this thread or this thread

Focus a field

  • To make sure the field is rendered:
editFormWindow.on('activate', function () {

Using Enter to Tab through Form

See this thread

Change field based on value of another field

  • Changing "to" date based on value in "from" date (+10 days):
dateFrom.on('change', function(f, value) {
   dateTo.setValue(value.add(Date.DAY, 10));

Change textfield config options with listeners

  • For example, if you make a selection on combobox, have it check if the value = 1. If so then textfield allowBlank: false else textfield allowBlank: true.
myCombo.on('select', function(cmb, rec) {
  var val = rec.get('someField');
  myTextfield.allowBlank = (val == 1);
  myTextfield.validate();//to force validation.

Standard Submit

  • You may need to use this to set the action:
PANEL.getForm().getEl().dom.action = 'URL'

Get all form fields

  • To pass the entire contents of the form as params, use:
    params: formPanel.getForm().getValues(false)

Fieldset Checkbox Toggle State

  • To alter the checked/unchecked state of the fieldset dynamically, try:
//where 'images-view' is the id for the fieldset
//To check the value of the checkbox on the fieldset

Error Message after a load action

Ext.override(Ext.form.BasicForm, {
    load: function(options){
        //default load options
        var _options = {
            //define failure method
            //use handleResponse method of Action.Submit as a guide
            failure: function(form, action){
                if (form.errorReader) {
                    var rs =;
                    var errors = [];
                    if (rs.records) {
                        for (var i = 0, len = rs.records.length; i < len; i++) {
                            var r = rs.records<i>;
                            errors<i> =;
                    if (errors.length < 1) {
                        errors = null;
                    action.result = {
                        success: rs.success,
                        errors: errors
                else {
                    action.result = Ext.decode(action.response.responseText);
        //specific load options
        Ext.apply(_options, options);
        //do the load
        this.doAction('load', _options);
        return this;

Modifying a date in a form to send to back end

  • Option 1: Use this plugin with your FormPanel to allow you to specify a getSubmitValue() method which you can then customize to your heart's content.
  • Option 2:
 * An example of modifying the format of a date field in a form
 * in order to pass the the date in mysql format
    //modify date to different format
    function getDateValue(obj, format){
        var strReturn = '';
        try {
            strReturn = obj.getValue().format(format).trim();
        catch (err) {
            strReturn = '';
        return strReturn;
    var formPlan = new Ext.FormPanel({
        labelWidth: 75,
        frame: true,
        title: 'New Plan',
        waitMsgTarget: true,
        monitorValid: true,
        width: 350,
        defaults: {
            width: 210,
            msgTarget: 'side'
        defaultType: 'textfield',
        items: [new Ext.form.DateField({
            fieldLabel: 'Start',
            id: 'date_start', // give id so can refer to this field more easily
            name: 'date_start',
            format: 'F j, Y',
            allowBlank: false
        buttons: [{
            text: 'New',
            formBind: true,
            handler: function(){
                    url: 'ajax/plan.php',
                    method: 'POST',
                    params: {
                        action: 'new',
                        //modify date
                        date_value1: getDateValue(Ext.get('date_start'), 'Ymd')
                    waitMsg: 'Saving Data...',
                    success: function(form, action){
                        Ext.MessageBox.alert('Message', 'Plan saved.');
                    failure: function(form, action){
                        Ext.MessageBox.alert('Message', 'Save failed');
        }, {
            text: 'Cancel',
            handler: function(){

Set height for TextArea component

Hide Form Fields

HTML in forms

  • if you just want to add text to a form panel like you mentioned, you may use a label as below:
    xtype: "label",
    name: "rotate",
    id: 'label_id',
    text: "Your text goes here",
    cls: 'x-form-item-label x-form-item' /*apply ext styles*/
  • or if you would like to insert proper HTML (div, span, etc....), you may use:
    xtype: "box",
    autoEl: {
        tag: 'div',
        id: id,
        children: [{
            tag: 'div',
            style: 'margin:0 0 4px 0',
            html: 'Your HTML bits here'

Forms across multiple tabs

My Combobox in a tab, or card layout does not assume the correct width

Containers which are rendered hidden should be configured with

hideMode: 'offsets'

So that they are able to perform size calculations.

Textfield background color

  style:'background-color:yellow; background-image: none;'

So that they are able to perform size calculations.

Set allowBlank dynamically

myField.allowBlank = true;
myField.validateValue(myField.getValue()); //force update

Set fieldLabel dynamically

Ext.override(Ext.form.Field, {
    setFieldLabel: function(text) {
        if (this.rendered) {
            var labelSeparator = this.labelSeparator;
            if (typeof labelSeparator == 'undefined') {
                if (this.ownerCt && this.ownerCt.layout && typeof this.ownerCt.layout.labelSeparator != 'undefined')
                    labelSeparator = this.ownerCt.layout.labelSeparator;
                    labelSeparator = '';
            var formItem = this.el.up('.x-form-item', 10);
            if (formItem) {
                var label = formItem.child('.x-form-item-label');
                if (label)
                    label.update(text + labelSeparator);
        } else
            this.fieldLabel = text;


To have an event which will fire immediately after a value is entered in the date field try this override:

Ext.override(Ext.form.DateField, {
    menuListeners : {
        select: function(m, d){
            this.fireEvent('select', this, d);
        show : function(){ // retain focus styling
        hide : function(){
            this.focus.defer(10, this);
            var ml = this.menuListeners;
  "select",,  this);
  "show",,  this);
  "hide", ml.hide,  this);


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Written by The Sencha Dev Team

1 Comment


4 years ago
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