I'm developing an app with Angular and Semantic-UI. The app should be accessible, this means it should be compliant with WCAG 2.0.
To reach this purpose the modals should keep focus within the dialog and prevents users from going outside or move with "tabs" between elements of the page that lays under the modal.
I have found some working examples, like the following:
JQuery dialog: https://jqueryui.com/dialog/#modal-confirmation
dialog HTML 5.1 element: https://demo.agektmr.com/dialog
ARIA modal dialog example:
http://w3c.github.io/aria-practices/examples/dialog-modal/dialog.html
(that I have reproduced on Plunker)
Here is my try to create an accessible modal with Semantic-UI: https://plnkr.co/edit/HjhkZg
As you can see I used the following attributes:
role="dialog"
aria-labelledby="modal-title"
aria-modal="true"
But they don't solve my issue. Do you know any way to make my modal keeping focus and lose it only when user click on cancel/confirm buttons?
There is currently no easy way to achieve this. The inert attribute was proposed to try to solve this problem by making any element with the attribute and all of it's children inaccessible. However, adoption has been slow and only recently did it land in Chrome Canary behind a flag.
Another proposed solution is making a native API that would keep track of the modal stack, essentially making everything not currently the top of the stack inert. I'm not sure the status of the proposal, but it doesn't look like it will be implemented any time soon.
So where does that leave us?
Unfortunately without a good solution. One solution that is popular is to create a query selector of all known focusable elements and then trap focus to the modal by adding a keydown event to the last and first elements in the modal. However, with the rise of web components and shadow DOM, this solution can no longer find all focusable elements.
If you always control all the elements within the dialog (and you're not creating a generic dialog library), then probably the easiest way to go is to add an event listener for keydown on the first and last focusable elements, check if tab or shift tab was used, and then focus the first or last element to trap focus.
If you're creating a generic dialog library, the only thing I have found that works reasonably well is to either use the inert polyfill or make everything outside of the modal have a tabindex=-1.
var nonModalNodes;
function openDialog() {
var modalNodes = Array.from( document.querySelectorAll('dialog *') );
// by only finding elements that do not have tabindex="-1" we ensure we don't
// corrupt the previous state of the element if a modal was already open
nonModalNodes = document.querySelectorAll('body *:not(dialog):not([tabindex="-1"])');
for (var i = 0; i < nonModalNodes.length; i++) {
var node = nonModalNodes[i];
if (!modalNodes.includes(node)) {
// save the previous tabindex state so we can restore it on close
node._prevTabindex = node.getAttribute('tabindex');
node.setAttribute('tabindex', -1);
// tabindex=-1 does not prevent the mouse from focusing the node (which
// would show a focus outline around the element). prevent this by disabling
// outline styles while the modal is open
// #see https://www.sitepoint.com/when-do-elements-take-the-focus/
node.style.outline = 'none';
}
}
}
function closeDialog() {
// close the modal and restore tabindex
if (this.type === 'modal') {
document.body.style.overflow = null;
// restore or remove tabindex from nodes
for (var i = 0; i < nonModalNodes.length; i++) {
var node = nonModalNodes[i];
if (node._prevTabindex) {
node.setAttribute('tabindex', node._prevTabindex);
node._prevTabindex = null;
}
else {
node.removeAttribute('tabindex');
}
node.style.outline = null;
}
}
}
The different "working examples" do not work as expected with a screenreader.
They do not trap the screenreader visual focus inside the modal.
For this to work, you have to :
Set the aria-hidden attribute on any other nodes
disable keyboard focusable elements inside those trees (links using tabindex=-1, controls using disabled, ...)
The jQuery :focusable pseudo selector can be useful to find focusable elements.
add a transparent layer over the page to disable mouse selection.
or you can use the css pointer-events: none property when the browser handles it with non SVG elements, not in IE
This focus-trap plugin is excellent at making sure that focus stays trapped inside of dialogue elements.
It sounds like your problem can be broken down into 2 categories:
focus on dialog box
Add a tabindex of -1 to the main container which is the DOM element that has role="dialog". Set the focus to the container.
wrapping the tab key
I found no other way of doing this except by getting the tabbable elements within the dialog box and listening it on keydown. When I know the element in focus (document.activeElement) is the last one on the list, I make it wrap
"focus" events can be intercepted in the capture phase, so you can listen for them at the document.body level, squelch them before they reach the target element, and redirect focus back to a control in your modal dialog. This example assumes a modal dialog with an input element gets displayed and assigned to the variable currDialog:
document.body.addEventListener("focus", (event) => {
if (currDialog && !currDialog.contains(event.target)) {
event.preventDefault();
event.stopPropagation();
currDialog.querySelector("input").focus();
}
}, {capture: true});
You may also want to contain such a dialog in a fixed-position, clear (or low-opacity) backdrop element that takes up the full screen in order to capture and suppress mouse/pointer events, so that no browser feedback (hover, etc.) occurs that could give the user the impression that the background is active.
Don't use any solution requiring you to look up "tabbable" elements. Instead, use keydown and either click events or a backdrop in an effective manor.
(Angular1)
See Asheesh Kumar's answer at https://stackoverflow.com/a/31292097/1754995 for something similar to what I am going for below.
(Angular2-x, I haven't done Angular1 in a while)
Say you have 3 components: BackdropComponent, ModalComponent (has an input), and AppComponent (has an input, the BackdropComponent, and the ModalComponent). You display BackdropComponent and ModalComponent with the correct z-index, both are currently displayed/visible.
What you need to do is have a general window.keydown event with preventDefault() to stop all tabbing when the backdrop/modal component is displayed. I recommend you put that on a BackdropComponent. Then you need a keydown.tab event with stopPropagation() to handle tabbing for the ModalComponent. Both the window.keydown and keydown.tab could probably be in the ModalComponent but there is purpose in a BackdropComponent further than just modals.
This should prevent clicking and tabbing to the AppComponent input and only click or tab to the ModalComponent input [and browser stuffs] when the modal is shown.
If you don't want to use a backdrop to prevent clicking, you can use use click events similarly to the keydown events described above.
Backdrop Component:
#Component({
selector: 'my-backdrop',
host: {
'tabindex': '-1',
'(window:keydown)': 'preventTabbing($event)'
},
...
})
export class BackdropComponent {
...
private preventTabbing(event: KeyboardEvent) {
if (event.keyCode === 9) { // && backdrop shown?
event.preventDefault();
}
}
...
}
Modal Component:
#Component({
selector: 'my-modal',
host: {
'tabindex': '-1',
'(keydown.tab)': 'onTab($event)'
},
...
})
export class ModalComponent {
...
private onTab(event: KeyboardEvent) {
event.stopPropagation();
}
...
}
Here's my solution. It traps Tab or Shift+Tab as necessary on first/last element of modal dialog (in my case found with role="dialog"). Eligible elements being checked are all visible input controls whose HTML may be input,select,textarea,button.
$(document).on('keydown', function(e) {
var target = e.target;
var shiftPressed = e.shiftKey;
// If TAB key pressed
if (e.keyCode == 9) {
// If inside a Modal dialog (determined by attribute role="dialog")
if ($(target).parents('[role=dialog]').length) {
// Find first or last input element in the dialog parent (depending on whether Shift was pressed).
// Input elements must be visible, and can be Input/Select/Button/Textarea.
var borderElem = shiftPressed ?
$(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').first()
:
$(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').last();
if ($(borderElem).length) {
if ($(target).is($(borderElem))) {
return false;
} else {
return true;
}
}
}
}
return true;
});
we can use the focus trap npm package.
npm i focus-trap
This might help someone who is looking for solution in Angular.
Step 1: Add keydown event on dialog component
#HostListener('document:keydown', ['$event'])
handleTabKeyWInModel(event: any) {
this.sharedService.handleTabKeyWInModel(event, '#modal_id', this.elementRef.nativeElement, 'input,button,select,textarea,a,[tabindex]:not([tabindex="-1"])');
}
This will filters the elements which are preseneted in the Modal dialog.
Step 2: Add common method to handle focus in shared service (or you can add it in your component as well)
handleTabKeyWInModel(e, modelId: string, nativeElement, tagsList: string) {
if (e.keyCode === 9) {
const focusable = nativeElement.querySelector(modelId).querySelectorAll(tagsList);
if (focusable.length) {
const first = focusable[0];
const last = focusable[focusable.length - 1];
const shift = e.shiftKey;
if (shift) {
if (e.target === first) { // shift-tab pressed on first input in dialog
last.focus();
e.preventDefault();
}
} else {
if (e.target === last) { // tab pressed on last input in dialog
first.focus();
e.preventDefault();
}
}
}
}
}
Now this method will take the modal dialog native element and start evaluate on every tab key. Finally we will filter the event on first and last so that we can focus on appropriate elements (on first after last element tab click and on last shift+tab event on first element).
Happy Coding.. :)
I used one of the methods suggested by Steven Lambert, namely, listening to keydown events and intercepting "tab" and "shift+tab" keys. Here's my sample code (Angular 5):
import { Directive, ElementRef, Attribute, HostListener, OnInit } from '#angular/core';
/**
* This directive allows to override default tab order for page controls.
* Particularly useful for working around the modal dialog TAB issue
* (when tab key allows to move focus outside of dialog).
*
* Usage: add "custom-taborder" and "tab-next='next_control'"/"tab-prev='prev_control'" attributes
* to the first and last controls of the dialog.
*
* For example, the first control is <input type="text" name="ctlName">
* and the last one is <button type="submit" name="btnOk">
*
* You should modify the above declarations as follows:
* <input type="text" name="ctlName" custom-taborder tab-prev="btnOk">
* <button type="submit" name="btnOk" custom-taborder tab-next="ctlName">
*/
#Directive({
selector: '[custom-taborder]'
})
export class CustomTabOrderDirective {
private elem: HTMLInputElement;
private nextElemName: string;
private prevElemName: string;
private nextElem: HTMLElement;
private prevElem: HTMLElement;
constructor(
private elemRef: ElementRef
, #Attribute('tab-next') public tabNext: string
, #Attribute('tab-prev') public tabPrev: string
) {
this.elem = this.elemRef.nativeElement;
this.nextElemName = tabNext;
this.prevElemName = tabPrev;
}
ngOnInit() {
if (this.nextElemName) {
var elems = document.getElementsByName(this.nextElemName);
if (elems && elems.length && elems.length > 0)
this.nextElem = elems[0];
}
if (this.prevElemName) {
var elems = document.getElementsByName(this.prevElemName);
if (elems && elems.length && elems.length > 0)
this.prevElem = elems[0];
}
}
#HostListener('keydown', ['$event'])
onKeyDown(event: KeyboardEvent) {
if (event.key !== "Tab")
return;
if (!event.shiftKey && this.nextElem) {
this.nextElem.focus();
event.preventDefault();
}
if (event.shiftKey && this.prevElem) {
this.prevElem.focus();
event.preventDefault();
}
}
}
To use this directive, just import it to your module and add to Declarations section.
I've been successful using Angular Material's A11yModule.
Using your favorite package manager install these to packages into your Angular app.
**"#angular/material": "^10.1.2"**
**"#angular/cdk": "^10.1.2"**
In your Angular module where you import the Angular Material modules add this:
**import {A11yModule} from '#angular/cdk/a11y';**
In your component HTML apply the cdkTrapFocus directive to any parent element, example: div, form, etc.
Run the app, tabbing will now be contained within the decorated parent element.
For jquery users:
Assign role="dialog" to your modal
Find first and last interactive element inside the dialog modal.
Check if current target is one of them(depending on shift key is
pressed or not).
If target element is one of first or last interactive element of the
dialog, return false
Working code sample:
//on keydown inside dialog
$('.modal[role=dialog]').on('keydown', e => {
let target = e.target;
let shiftPressed = e.shiftKey;
// If TAB is pressed
if (e.keyCode === 9) {
// Find first and last element in the ,modal-dialog parent.
// Elements must be interactive i.e. visible, and can be Input/Select/Button/Textarea.
let first = $(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').first();
let last = $(target).closest('[role=dialog]').find('input:visible,select:visible,button:visible,textarea:visible').last();
let borderElem = shiftPressed ? first : last //border element on the basis of shift key pressed
if ($(borderElem).length) {
return !$(target).is($(borderElem)); //if target is border element , return false
}
}
return true;
});
I read through most of the answers, while the package focus-trap seems like a good option. #BenVida shared a very simple VanillaJS solution here in another Stack Overflow post.
Here is the code:
const container=document.querySelector("_selector_for_the_container_")
//optional: needed only if the container element is not focusable already
container.setAttribute("tabindex","0")
container.addEventListener("focusout", (ev)=>{
if (!container.contains(ev.relatedTarget)) container.focus()
})
I have a rather large form, that I've broken up into individual sections with "Next" and "Back" buttons for the user to navigate each step.
Here is how I set it up to work for now:
Each section is within its own xp:panel
Each xp:panel is hidden with "display:none". The transition happens when the user clicks on "Next" or "Back" by using JQuery's fade animation
What I am trying to do is, if the user clicks on "Next" I would like to validate only the fields in the current, visible section. If the validation fails, don't transition to the next step. If the validation passes, transition to the next step.
Right now, when I click on the "Next" button, every field is being validated and the transition doesn't happen.
Is there a way, that I can only validate the fields in a certain section or would I have to use something like Don Mottolo's code snippet: http://openntf.org/XSnippets.nsf/snippet.xsp?id=ssjs-form-validation-that-triggers-errormessage-controls
Thank you for your help!
P.S.: I know I could use the CSJS portion of the onClick event of the button to run some validation, but I'd like to use the "Display Error" controls.
You could look at computing the required attribute of each control that is to be validated and have that check which button is submitting the form. Tommy Vaaland has a function that does this:
// Used to check which if a component triggered an update
function submittedBy( componentId ){
try {
var eventHandlerClientId = param.get( '$$xspsubmitid' );
var eventHandlerId = #RightBack( eventHandlerClientId, ':' );
var eventHandler = getComponent( eventHandlerId );
if( !eventHandler ){ return false; }
var parentComponent = eventHandler.getParent();
if( !parentComponent ){ return false; }
return ( parentComponent.getId() === componentId );
} catch( e ){ /*Debug.logException( e );*/ }
}
Link: http://dontpanic82.blogspot.co.uk/2010/03/xpages-making-validation-behave.html
You can look at using a client side form validation framework such as Parsley: http://parsleyjs.org
This can of course be combined with server side validation for at least the final submission.
I don't use tab panel just tab bar, and have to prevent changing tab by some criteria.
In ExtJS docs I found change event for Ext.tab.Bar, but it fires when tab is already changed. So preventDefault() and return false are not working in this case.
Second I tried is set Ext.tab.Tab.handler property when tabs were initialized, but it fires when tab button is already clicked. So preventDefault() and return false don't work too.
Can ony body help with this? How can I prevent changing tabs using only Ext.tab.Tab and Ext.tab.Bar?
Thx.
I think you can use the 'beforetabchange' event on the tab panel itself.
From sencha docs: http://docs.sencha.com/ext-js/4-0/#!/api/Ext.tab.Panel-event-beforetabchange .
Return false in any listener to cancel the tabchange.
Edit
Maybe you could then extend the Ext.tab.Bar component and register the beforechange event by modifying the setActiveTab method, I think it's a pretty easy modification
setActiveTab: function(tab) {
//test the beforechange return
if (tab.disabled && me.fireEvent('beforechange', tab) === false) {
return;
}
var me = this;
if (me.activeTab) {
me.previousTab = me.activeTab;
me.activeTab.deactivate();
}
tab.activate();
if (me.rendered) {
me.layout.layout();
tab.el && tab.el.scrollIntoView(me.layout.getRenderTarget());
}
me.activeTab = tab;
me.fireEvent('change', me, tab, tab.card);
}
Add a controller action "beforeshow" on the tab panel container and disable the listeners. Allows the tabs to behave normally without clickability.
component.down("#tabPanel").tabBar.clearListeners();
In Jqgrid, I want to restrict user to select only one check box at any time. When user selects multiple check box only last selected to be in 'selected' state, remaining should be automatically un-selected.
I have set multi select attribute to true. But I am not able to do un-select previously selected item. Is it possible to do if so how?
Thanks
You can use the event beforeSelectRow and reset the selection:
beforeSelectRow: function(rowid, e)
{
jQuery("#list47").jqGrid('resetSelection');
return(true);
}
I've got a fiddle for you so you can check how it works.
You have to do some more stuff:
1. Set multiboxonly to true and multiselect to true
2. Define the events onSelectRow and beforeSelectRow:
3. Define global variable: var lastSel;
The OnSelectRow and beforeSelectRow implementation:
onSelectRow: function (rowId, status, e) {
if (rowId == lastSel) {
$(this).jqGrid("resetSelection");
lastSel = undefined;
status = false;
} else {
lastSel = rowId;
}
},
beforeSelectRow: function (rowId, e) {
$(this).jqGrid("resetSelection");
return true;
}
Having a checkbox in each column implies that you can click more than one at a time. What you are asking for is basically the multiselect: false behavior but with the checkbox column - are you sure you really want the checkboxes in this case?
I know this question is old, but I found a better solution in this Stack Post.
All you have to do is set the following two properties of the jqGrid:
multiselect:true // multi-select checkboxes appear
multiboxonly:true // checkboxes act like radio buttons where only one is selected at a time
I have updated the fiddle made by LeftyX to simply use the multiboxonly setting at this JsFiddle
This was what I needed. It may help someone else.
This is strange and any alternative method to what I want to accomplish is welcome. My app uses the jqgrid 3.5.3 and I need to disable a select list on my edit form. When I do so using the code displayed below it breaks the edit form - meaning I can not cancel or submit it. Thanks. This code is in the edit options array of the navGrid method. The the dropdown is the 'serv_descr' field. The others are text boxes and don't pose a problem. The form does come up and the field is disabled - its just broken.
beforeShowForm: function(eparams) {
document.getElementById('equip_id').disabled = true;
document.getElementById('service_dt').disabled = true;
document.getElementById('serv_descr').disabled = true;
document.getElementById('calc_next_svc').checked = 'true';
}
afterShowForm: function(eparams) {
$('#equip_id').attr('disabled', 'disabled');
$('#service_dt').attr('disabled', 'disabled');
$('#serv_descr').attr('disabled', 'disabled');
$('#calc_next_svc').attr('checked', true);
}
Note:
replace event trigger afterShowForm
id name must be form controll