Develop Reference

How to get an element with condition of modal dialog in Angular 2?

I'm using ng2-modal to create a modal dialog in Angular 2. I am unable to get an element that has a condition on it (#myModalScrollPanel).
Template (modal.html):
<modal #myModal title="{{title}}"
cancelButtonLabel="Close"
submitButtonLabel="Ok"
modalClass="#modal-md"
[hideCloseButton]="false"
[closeOnEscape]="false"
[closeOnOutsideClick]="false"
>
<modal-header></modal-header>
<modal-content>
<div class="row">
<div *ngIf="logOutput" class="col-md-12">
<div id="myModalScrollPanel" #myModalScrollPanel class="panel-body fixed-panel">
<p *ngFor="let entry of logOutput.entries">{{entry.log}}</p>
</div>
</div>
</div>
</modal-content>
<modal-footer></modal-footer>
</modal>
In my component I get View Children (modal.component.ts):
#ViewChild('myModal') myModalModal;
#ViewChild('myModalScrollPanel') myModalScrollPanel;
After a users clicks a button, I show the modal and get log text from the server, I call updateScrollPosition() once I have updated logOutput (modal.component.ts):
updateScrollPosition() {
console.log("modal:");
console.log(this.myModalModal);
console.log("log scroll panel:");
console.log(this.myModalScrollPanel);
if(this.myModalScrollPanel){
console.log("Scrolling the panel down");
this.myModalScrollPanel.nativeElement.scrollTop = this.myModalScrollPanel.nativeElement.scrollHeight;
} else {
console.log("No log scroll panel.");
}
}
The console shows a valid object for "modal" and 'undefined' for log scroll panel.
I also tried calling that method from ngAfterViewInit(), but it only gets called when the parent component is loaded, and not the actual modal being shown, so the if statement results in false and element doesn't exist yet. If I remove/move the if statement, so that the element exists I can then access that object, but the changes I make do not take any effect, although that might be a whole different issue (most likely to do with change detection).
In the end, I just want to scroll to the bottom of the panel. Something like this (which works in the browser console):
var scrollPanel = document.getElementById('myModalScrollPanel');
scrollPanel.scrollTop = scrollPanel.scrollHeight;
Thanks in advance!

So to answer my own question, I had to use #ViewChildren instead of #ViewChild.
#ViewChildren annotation will assign a QueryList object to your variable, giving you access to the elements you require (I use .toArray() to get an array of elements, which in this case will be just one).
Speaking of the change detection problem I had, thanks to this answer, using the ngAfterViewChecked() method I was able to implement the scroll down I needed.

How to create a see-more/Read-more feature requiring only anchors in the html?

I'm working on a site which will be maintained by not so tech savvy people, and I need to be able to give them the ability to add "see-more" anchors which use Jquery slide up/down to reveal their content.
My code works well for a single instance of the read more, but when there are multiple instances of this, it gets fairly screwed up.
javascript/jquery
$(".see-more").nextUntil(".see-less").wrapAll("<div class='see-more-content'></div>");
$(".see-less").hide();
var count= 1
/*
$(".see-more-content").each(function(){
var count= count+1;
$(this).data("count",count);
console.log(count);
});
*/
$(".see-more-content").slideUp(0);
$(".see-more").click(function(){
$(".see-more-content").slideToggle();
$(".see-more").hide();
$(".see-less").show();
});
$(".see-less").click(function(){
$(".see-more-content").slideToggle();
$(".see-less").hide();
$(".see-more").show();
});
HTML
<a class="see-more">See More...</a>
<ul>
<li>Advanced Elastic search Technology </li>
<li>Document Text Search</li>
<li>Embed Code Web Publishing for Images, Video & PDFs</li>
<li>Video Management with HTML5 Full</li>
<li>Previews On the Fly Conversions and Transcoding</li>
<li>Print on Demand</li>
<li>Stylized Collections (Lightboxes/Galleries)</li>
<li>Alerts and Notifications</li>
<li>Comments, Ratings and Favorites</li>
<li>WordPress and Drupal CMS Integrations</li>
<li>Dropbox Integration</li>
<li>Asset Level Performance Analytics • Site Activity Analytics Dashboard</li>
<li>Unlimited Custom User Access Levels</li>
<li>Integrated Content Contribution and Workflow</li>
<li>Personal Profile Management</li>
<li>Mobile App and Site </li>
<li>Watermarking</li>
<li>Rights Management</li>
<li>All New Feature Releases3</li>
</ul>
<a class="see-less">See Less...</a></div>
What I want to happen:
I want everything between the anchor with class see-more and anchor with class see-less, to get wrapped in a div, which when the anchor for see-more is clicked that div jquery slides down, when see-more is clicked, and slides up when see-less is clicked.
What is happening:
It works perfect when there is only one instance of see-more and see-less in a page. https://jsfiddle.net/TheWebTech/by3LsLuu/
When there are multiple instances of see-more and see-less in the html, the contents of all see-more+see-less blocks after the first instance are all moved/wrapped into the first block instances of the see-more see-less blocks get added.
https://jsfiddle.net/TheWebTech/by3LsLuu/4/
How do I prevent everything from being wrapped into the first instance of the see-more see-less block and instead have each one get wrapped separately?
Bonus but not really required: how can I make each see-more section slide up/down separately from eachother?

If you're going to keep the layout the same, you can use .prev() and .next() jQuery methods to determine which selector group you're referring too. Here's an updated fiddle with two instances:
https://jsfiddle.net/szva79d6/1/
First, I've made it so that your wrapping function applies to each selector individually, like so:
$(".see-more").each(function() {
$(this).nextUntil(".see-less")
.wrapAll("<div class='see-more-content'></div>");
});
What I've done in the two event methods is to make each event only act on the previous or next siblings, so that your events are properly delegated to each dynamically wrapped element.
$(".see-more").click(function() {
var $more = $(this),
$content = $more.next(".see-more-content"),
$less = $content.next(".see-less");
$content.slideToggle();
$more.hide();
$less.show();
});
$(".see-less").click(function() {
var $less = $(this),
$content = $less.prev(".see-more-content"),
$more = $content.prev(".see-more");
$content.slideToggle();
$less.hide();
$more.show();
});

You need to target specific to itself, try this:
$(".see-more").click(function(){
$(this).next(".see-more-content").slideToggle(); // find next content and show
$(this).hide(); // hide the see more button
$(this).nextAll('.see-less').first().show(); // show the next see less button
});
$(".see-less").click(function(){
$(this).prev(".see-more-content").slideToggle();
$(this).hide();
$(this).prevAll(".see-more").first().show();
});
Here's an updated fiddle

JQuery Mobile dynamic listview loses style (data-inset) after updating

I am creating a mobile app (Phonegap/Cordova 1.5.0, JQM 1.1.0) and testing on iOS 5.1. I have a list of items that the user "owns" or wants to own. Throughout the app, the user can edit their list by adding and removing items. Whenever items are added or removed, the list updates, and it is displaying fine, with all of the JQuery CSS intact except the corners are no longer rounded (I'm thinking because data-inset is getting set to "false").
Here is my html for the list-headers:
<div data-role="page" id="profile">
<div data-role="header" data-position="fixed">
<...>
</div><!-- /header -->
<div data-role="content" data-theme="a">
<...>
<ul id="user-wants-list" data-role="listview" data-inset="true" data-theme="d" data-dividertheme="d" >
</ul> <!--/Wants list-->
</br>
<ul id="user-haves-list" data-role="listview" data-inset="true" data-theme="d" data-dividertheme="d" >
</ul> <!--/Has list-->
</br></br>
</div> <!--/content-->
</div> <!--/Profile-->
And here is the Javascript where I remove the old list and dynamically add the new one (the parameter 'haves' is an array of objects):
function displayHaves(haves){
var parent = document.getElementById('user-haves-list');
removeChildrenFromNode(parent);
parent.setAttribute('data-inset','true');
$(parent).listview("refresh");
var listdiv = document.createElement('li');
listdiv.setAttribute('id','user-haves-list-divider');
listdiv.setAttribute('data-role','list-divider');
listdiv.innerHTML = "I Have (" + haves.length + ")";
parent.appendChild(listdiv);
//create dynamic list
for(i=0;i<haves.length;i++){
var sellListing = haves[i].listing;
var userInfo = haves[i].user;
var itemData = haves[i].item;
//create each list item
var listItem = document.createElement('li');
listItem.setAttribute('id','user-haves-list-item-'+i);
parent.appendChild(listItem);
var link = document.createElement('a');
link.setAttribute('id','user-haves-link-' + i);
new FastButton(link, function(listing) {
return function() { displaySellListingPage(listing); }
}(sellListing));
listItem.appendChild(link);
var link = document.getElementById('user-haves-link-' + i);
var pic = document.createElement('img');
pic.setAttribute('src',itemData.pictureURL);
pic.setAttribute('width','80px');
pic.setAttribute('height','100px');
pic.setAttribute('style','padding-left: 10px');
link.appendChild(pic);
var list = document.getElementById('user-haves-list');
$(list).listview("refresh");
}
}
and my function removeChildrenFromNode(parent) is as follows:
function removeChildrenFromNode(node){
while (node.hasChildNodes()){
node.removeChild(node.firstChild);
}
}
So my question is, why does the listview lose the data-inset attribute?
Or, equally valid: is there another way I could/should be achieving corner rounding besides "data-inset='true'"?
Here are things I have tried:
using .trigger("create") on both the listview and the page
adding the listview with explicit styling each time by using $("#page-ID").append(...)
I read another post on StackOverflow that said that JQM creates some inner elements when you create an item (this post had to do with dynamic buttons not being the right size), and that there are some classes (like .ui-btn) that you can access (that may be losing styling when I remove the children from the node?), but I was unable to make any headway in that direction.
Thanks in advance for the help!

I figured out the answer to my question, but not a solution (yet).
$(list).listview('refresh') was getting called on some elements before they had been put on the page, so it was essentially being called on nothing (or another way to think about it is that each list item being appended happens after the refresh call, so it overrides some of the visual styling).
I know the problem has to do with asynchronous loading in javascript. Essentially, the .listview('refresh) executes before the earlier code, which creates the elements but takes longer to execute. I understand the reasoning behind the design, but is there some way to get around this in this case?
I am thinking some conditional that I could set, like:
var doneLoading = false;
//Then when finished set doneLoading to 'true'
if(doneLoading) $(list).listview('refresh');
but if the refresh gets called first, I figure that doneLoading will just evaluate to false and then not execute once the list is actually done loading.
Is there any kind of onComplete callback I can use, or a way to make it happen synchronously?

Try calling listview(refresh) after updating the HTML.

(jQuery) Find and Replace specific text

I've got the following HTML code, which essentially pertains to a post where I announce something in just a few lines, end it with "[...]", and add a "Read more" link-button at the bottom. When this button is clicked, additional content that's hidden will fadeIn as the button disappears, leaving visible the introductory text and the one that was hidden -- simple enough. Now, I've already written the code for this, but the complication comes when I try to also remove that "[...]" (from the post where the click button happened) that I included in the sneak peek. Here's the HTML:
<div class="entry">
<p>Welcome. Talk about something briefly and click below for more. [...]</p>
<div class="slide-content">
<p>Hidden content.</p>
</div>
<span id="revealer" class="button">Read more</span>
</div>
Classes "entry" and "button" belong to my CSS file, while "slide-content" belongs to my .js file to control the fadeIn effect. The ID "revealer" also belongs to the .js file for the same purpose. This HTML is wrapped in a div tag with a class of "box". This is the format that each post follows, exactly the same format with the same HTML elements -- every time an announcement needs to be made, it's just a matter of putting the content between the paragraph tags and publish. Here is where my problem comes in, since I can't find a way to remove the "[...]" only in the post where the button has been clicked. I tried doing the following but it resulted in the deletion of all "[...]" throughout multiple posts:
$('.entry p').each(function() {
var textReplace = $(this).text();
$(this).text(textReplace.replace('[...]', ''));
});
Summary:
I need to remove the "[...]" text only from the post where the user has clicked on (the "Read more" button). The idea is to have this removed while at the same time the hidden content fades in.
I've been able to accomplish the above but for all instances of "[...]". I need to sophisticate my selection by modifying my jQuery code or the HTML.
Option 3 is to get rid of this "[...]", but I would like to leave it there to let the user know she has more content to read, and I would like to have that "Read more" button in all posts for consistency.
~Thanks in advance!

First, you mention you have multiple of these. In that case, this:
<span id="revealer" class="button">Read more</span>
will not work. id attribute has to be unique per document, i.e. you can have at most one element with the specific id value.
If you make your HTML (for each of the blocks) like this:
<div class="entry">
<p>Welcome. Talk about something briefly and click below for more. [...]</p>
<div class="slide-content">
<p>Hidden content.</p>
</div>
<span class="revealer button">Read more</span>
</div>
and your JS like this:
function replace(fromp) {
var textReplace = fromp.text();
fromp.text(textReplace.replace('[...]', ''));
}
$('.revealer').click(function() {
var fromp = $(this).siblings().eq(0);
replace(fromp);
});
it will work properly. Working example:
http://jsfiddle.net/G4t7Q/
Hope this helps.

When you run your page initialization script, you could use jquery to select all of the posts and all of the remove buttons and link them up via their click event. I've created a JSFiddle example, but here's the jist of it:
var removers = $(".remover")
var posts = $(".post")
for (var i = 0; i < removers.length; i++) {
$(removers[i]).click( { post: posts[i] },
function(event) {
var textReplace = $(event.data.post).text()
$(event.data.post).text(textReplace.replace('[...]', ''))
}
)
}​
This is a simplified example; it assumes the posts and buttons are sorted in the markup.

Getting screen reader to read new content added with JavaScript

When a web page is loaded, screen readers (like the one that comes with OS X, or JAWS on Windows) will read the content of the whole page. But say your page is dynamic, and as users performing an action, new content gets added to the page. For the sake of simplicity, say you display a message somewhere in a <span>. How can you get the screen reader to read that new message?

The WAI-ARIA specification defines several ways by which screen readers can "watch" a DOM element. The best supported method is the aria-live attribute. It has modes off, polite,assertive and rude. The higher the level of assertiveness, the more likely it is to interrupt what is currently being spoken by the screen reader.
The following has been tested with NVDA under Firefox 3 and Firefox 4.0b9:
<!DOCTYPE html>
<html>
<head>
<script src="js/jquery-1.4.2.min.js"></script>
</head>
<body>
<button onclick="$('#statusbar').html(new Date().toString())">Update</button>
<div id="statusbar" aria-live="assertive"></div>
</body>
The same thing can be accomplished with WAI-ARIA roles role="status" and role="alert". I have had reports of incompatibility, but have not been able to reproduce them.
<div id="statusbar" role="status">...</div>

Here is an adapted real world example -- this up-level markup has already been converted from an unordered list with links into a select menu via JS. The real code is a lot more complex and obviously could not be included in its entirety, so remember this will have to be rethought for production use. For the select menu to be made keyboard accessible, we registered the keypress & onchange events and fired the AJAX call when users tabbed off of the list (beware of browser differences in timing of the onchange event). This was a serious PITA to make accessible, but it IS possible.
// HTML
<!-- select element with content URL -->
<label for="select_element">State</label>
<select id="select_element">
<option value="#URL_TO_CONTENT_PAGE#" rel="alabama">Alabama</option>
</select>
<p id="loading_element">Content Loading</p>
<!-- AJAX content loads into this container -->
<div id="results_container"></div>
// JAVASCRIPT (abstracted from a Prototype class, DO NOT use as-is)
var selectMenu = $('select_element');
var loadingElement = $('loading_element');
var resultsContainer = $('results_container');
// listen for keypress event (omitted other listeners and support test logic)
this.selectMenu.addEventListener('keypress', this.__keyPressDetector, false);
/* event callbacks */
// Keypress listener
__keyPressDetector:function(e){
// if we are arrowing through the select, enable the loading element
if(e.keyCode === 40 || e.keyCode === 38){
if(e.target.id === 'select_element'){
this.loadingElement.setAttribute('tabIndex','0');
}
}
// if we tab off of the select, send focus to the loading element
// while it is fetching data
else if(e.keyCode === 9){
if(targ.id === 'select_element' && targ.options[targ.selectedIndex].value !== ''){
this.__changeStateDetector(e);
this.loadingElement.focus();
}
}
}
// content changer (also used for clicks)
__changeStateDetector:function(e){
// only execute if there is a state change
if(this.selectedState !== e.target.options[e.target.selectedIndex].rel){
// get state name and file path
var stateName = e.target.options[e.target.selectedIndex].rel;
var stateFile = e.target.options[e.target.selectedIndex].value;
// get the state file
this.getStateFile(stateFile);
this.selectedState = stateName;
}
}
getStateFile:function(stateFile){
new Ajax.Request(stateFile, {
method: 'get',
onSuccess:function(transport){
// insert markup into container
var markup = transport.responseText;
// NOTE: select which part of the fetched page you want to insert,
// this code was written to grab the whole page and sort later
this.resultsContainer.update(markup);
var timeout = setTimeout(function(){
// focus on new content
this.resultsContainer.focus();
}.bind(this), 150);
}.bind(this)
});
}

It really depends whether you are just adding some messages or replacing large parts of the page.
Messages
There are Aria Live Regions, which announce any change to their contents. This is very useful for status messages and sometimes even used with visually hidden live regions to only address screen reader users.
<button onclick="document.querySelector('#statusbar').innerHTML = new Date().toString()">Update</button>
<div id="statusbar" aria-live="assertive"></div>
The aria-live attribute establishes a live region and its value is a politeness setting, which regulates how likely it is the change will interrupt what is currently being spoken by the screen reader.
Another classic example is inline validation of form fields, where the alert role, a live region, is used to immediately announce the error message to the user:
<label>Day of the week we hate
<input type="text" aria-describedby="error">
</label>
<div role="alert" id="error" hidden>only Monday is permitted</div>
Large Parts of Content
When JavaScript is changing large parts of the site, like in single page applications, putting everything inside a live region would be overkill and actually very annoying.
To let the user know that content changed after activating a trigger, two approaches exist:
A new state of the trigger is announced, implying that the user can simply continue reading to find the new content
Focus is put either onto the element who’s content changed, or on the first interactive element inside
Simply read on
The first case would be applied if the role of the trigger (or other status information) makes it clear that a content change will happen, so it’s expected.
A classic example is the accordion. It has aria-expanded state, which communicates whether its contents are currently visible or not. If they are, the user will simply continue reading, because contents should follow immediately after.
toggleAccordion = e => {
const target = document.getElementById(e.currentTarget.getAttribute('aria-controls'));
e.currentTarget.setAttribute('aria-expanded', ! target.toggleAttribute('hidden'));
}
<!-- soon to be replaced by <details> and <summary> -->
<button aria-expanded="false" aria-controls="accordion-content" onclick="toggleAccordion(event)">2.1 First Rule of ARIA Use</button>
<blockquote id="accordion-content" hidden>
<p>If you can use a native HTML element [HTML51] or attribute with the semantics and behavior you require already built in, instead of re-purposing an element and adding an ARIA role, state or property to make it accessible, then do so. […]</p>
</blockquote>
Put focus on the new content
In the second case focus is set programmatically elsewhere, so that element will be announced. This is particularly helpful if it’s parent elements have grouping roles, so their names will be announced as well, as in the case of a modal dialog.
Another example would be a single page application’s navigation, where the single navigation items are still navigated by means of tab.
To be able to programmatically focus a non-interactive element, but not manually, tabindex="-1" is necessary. Focussing the headline is a best practice.
/* some sort of SPA router */
document.querySelectorAll('nav a').forEach(a => a.addEventListener('click', e => {
// hide all visible contents
document.querySelectorAll('main > :not([hidden])').forEach(c => c.hidden = true);
document.querySelectorAll('[aria-current]').forEach(c => c.removeAttribute('aria-current'));
// show selected content
const content = document.querySelector(e.currentTarget.getAttribute('href'));
content.hidden = false;
content.querySelector('h1').focus();
e.currentTarget.setAttribute('aria-current', 'page');
}));
a[aria-current] { font-weight: bold }
<nav>
<ul>
<li>Page 1</li>
<li>Page 2</li>
</ul>
</nav>
<main>
<div id="page-1">
<h1 tabindex="-1">Page 1</h1>
<p>Many lines of content to follow</p>
</div>
<div id="page-2" hidden>
<h1 tabindex="-1">Page 2</h1>
<p>Many lines of content to follow</p>
</div>
</main>