Develop Reference

Toggling an element that appears twice on a page

I am working with an html component that appears twice on a page.
The issue I am having is that when I click one component to toggle it's content (like an accordion) both components toggle simultaneously.
How can I rewrite the JS to toggle each component when I click them separately, without giving the components different classes and rewriting the js twice?
This is what I have so far;
var bindEventsToUI = function () {
$(".details").click(function(e){
$(".content").slideToggle("slow", function() {
$(e.target).hide().siblings().show();
});
});
};

Try this:
$(".details").click(function(e) {
$(this).children(".content").slideToggle("slow");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class='details'>Testing 123
<div class='content'>> Content 123</div>
</div>
<div class='details'>Testing 456
<div class='content'>> Content 456</div>
</div>

You will need to have a different identifier for each element. I would recommend an id:
var bindEventsToUI = function () {//element) {
$("#id1 .details").click(function(e){
$("#id1 .content").slideToggle("slow", function() {
$(e.target).hide().siblings().show();
});
});
$("#id2 .details").click(function(e){
$("#id2 .content").slideToggle("slow", function() {
$(e.target).hide().siblings().show();
});
});
//..and so on
};
Or, you could use the closest function:
var bindEventsToUI = function () {//element) {
$(".details").click(function(e){
$(this).closest(".content").slideToggle("slow", function() {
$(e.target).hide().siblings().show();
});
});
};

JavaScript: using THIS inside object function and binding event

I have an Object and I want to bind a function to a button when Object was initialized.
var MyClass = {
Click: function() {
var a = MyClass; // <---------------------- look here
a.Start();
},
Bind: function() {
var a = document.getElementById('MyButton');
a.addEventListener('click', this.Click, false); //<---------- and here
},
Init: function() {
this.Bind();
}
}
So, I'm new at using it and I don't know if object can be declared like this (inside Click() function that should be done after clicking a button):
Is it a bad practise? Which could be the best way in this case when adding an event here?
Edit: fiddle

Firstly you have a syntax error. getElementsById() should be getElementById() - no s. Once you fix that, what you have will work, however note that it's not really a class but an object.
If you did want to create this as a class to maintain scope of the contained methods and variables, and also create new instances, you can do it like this:
var MyClass = function() {
var _this = this;
_this.click = function() {
_this.start();
};
_this.start = function() {
console.log('Start...');
}
_this.bind = function() {
var a = document.getElementById('MyButton');
a.addEventListener('click', this.click, false);
};
_this.init = function() {
_this.bind();
};
return _this;
}
new MyClass().init();
<button id="MyButton">Click me</button>

For event listeners it's easiest and best to use jQuery, for example if you want to have some .js code executed when user clicks on a button, you could use:
https://api.jquery.com/click/
I don't know how new you are to .js, but you should look up to codecademy tutorials on JavaScript and jQuery.
.click() demo:
https://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_event_click

How can I read ".on()" method arguments in jQuery?

I have no idea how to bite this problem. Below two examples are working great but I want to avoid the DRY problem.
parentElement.on('focusout', '.foo-class', function () {
// console.log('hello foo')
});
and:
parentElement.on('focusout', '.bar-class', function () {
// console.log('hello bar')
});
I would like to make it more universal. I have to deal with two classes while the parent stays the same.
Assuming that this is the first step:
parentElement.on('focusout', classValue, function () {
// How to display this class so I can call different stuff depending on the class value?
// console.log('hello ' + classValue)
});

May be something along these line, refined from guardio's solution.
Fiddle: https://jsfiddle.net/pvorhknv/2/
What it doing here is to get the element been called for the handler and accessing the attributes. You can use this element "this" for any such use.
$(document).on('focusout', 'input', callme);
function callme(){
console.log('hello ' + $(this).attr('class').split('-')[0])
}
UPDATE:
One other thing you can use it to mark data attribute for the elements.
Fiddle: https://jsfiddle.net/pvorhknv/3/
<input type='text' class='foo-class' data-classname="foo">
<input type='text' class='bar-class' data-classname="bar">
And hence you can access them,
function callme(){
console.log('hello ' + $(this).data('classname'));
}

To look if the (1) element has a particular class, and to (2) get all classes of $(this), see following:
parentElement.on('focusout', classValue, function () {
// (1). find out if element has class 'foo-class'
if $(this).hasClass('foo-class'){
// ...
}
// (2). for each class of element do something
$($(this).attr('class').split(' ')).each(function() {
if (this !== '') {
// ...
}
});
)};

You can use data attribute for specify event which you want to run. My solution is below (simple nothing more nothing less):
html
<div class="event" data-color-event="blue">click me = blue</div>
js
// one listener
$('body').on('click', '.event', function() {
var ev = $(this).data('color-event');
$('body')[ev]();
});
// event functions on demand
$.fn.blue = function() {
alert('blue');
}
$.fn.red = function() {
alert('red');
}
JSFIDDLE DEMO

Separate your classes with commas, and then check the class in the callback.
https://jsfiddle.net/guanzo/dmpgxxt0/
$('.container').on('click','.test1,.test2',function(){
console.log($(this).attr('class'))
})

Did you try
parentElement.on('focusout', '.foo-class, .bar-class', function () {
// console.log('hello foo')
});
And more:
parentElement
.on('focusout', '.foo-class, .bar-class', function () {
// console.log('hello foo')
})
.on('click', '.baz-class', function() { alert('xx'); })
;

Jasmine doesn't seem to be calling my method

I am new to Jasmine and seem to be struggling to get what I think is a fairy standard kind of thing running.
I am loading an HTML file via a fixture and trying to call a click on an element on the dom. This I would expect result in the call to the method of the JS file I am trying to test. When I try and debug this in developer tools the method that should be called in my js file never hits a breakpoint. As such I assume that code is not being called and therfore does not toggle the expand/collapse class.
My test:
describe("userExpand", function () {
beforeEach(function () {
loadFixtures('user-expand.html');
//userControl();
//this.addMatchers({
// toHaveClass: function (className) {
// return this.actual.hasClass(className);
// }
//});
});
//this test works ok
it("checks the click is firing", function () {
spyOnEvent($('.expanded'), 'click');
$('.expanded').trigger('click');
expect("click").toHaveBeenTriggeredOn($('.expanded'));
});
//this doesn't
it("checks the click is changing the class", function () {
//spyOnEvent($('.collapsed'), 'click');
var myElement = $('.collapsed');
myElement.click();
expect(myElement).toHaveClass('.expanded');
});
Part of the fixture:
<div class="wrapper">
<div class="row group">
<div class="col-md-1" data-bordercolour=""> </div>
<div class="collapsed col-md-1"> </div>
<div class="col-md-9">None (1)</div>
The JS I am trying to test:
var userControl = function () {
"use strict";
var collapse = '.collapsed';
var expand = '.expanded';
var userList = $(".userList");
function toggleState() {
var currentControl = $(this);
if (currentControl.hasClass('all')) {
if (currentControl.hasClass('expanded')) {
toggleIcon(currentControl, collapse);
userList.find(".user-group-summary").hide()
.end()
.find(".user-group-info").show();
} else {
toggleIcon(currentControl, expand);
userList.find(".user-group-summary").show()
.end()
.find(".user-group-info").hide();
}
} else {
currentControl.parent().nextUntil('.group').toggle();
currentControl.toggleClass("expanded collapsed");
currentControl.parent().find(".user-group-summary").toggle()
.end()
.find(".user-group-info").toggle();
}
};
function toggleIcon(ctrl, currentState) {
var details = ctrl.closest('div.row').siblings('.wrapper');
details.find(currentState).toggleClass('expanded collapsed');
if (currentState === expand) {
details.find('.detail').hide();
} else {
details.find('.detail').show();
}
}
userList.on('click', '.expanded, .collapsed', toggleState);
$('[data-bordercolour]').each(function () {
$(this).css("background-color", $(this).data('bordercolour'))
.parent().nextUntil('.group')
.find('>:first-child').css("background-color", $(this).data('bordercolour'));
});
return {
toggleState: toggleState
};
}();
The code works fine in normal use so I am sure I am missing something obvious with the way Jasmine should be used. Any help would be appreciated.
Update:
I can make the togglestate method fire by using call in the test rather than triggering a click event:
it('checks on click of icon toggles that icon', function () {
var myElement = $('.collapsed');
userControl.toggleState.call(myElement);
expect(myElement).toHaveClass('expanded');
});
This seems a little strange as all the examples I can find are quite happy with click. Gets me off the hook but I would still like to know what I am missing.

It's hard to give a precise hint without the source code. Does click on .collapsed involve asynchronous action(s)? If so, wrapping the test in runs(...); waitsFor(...); runs(...); may solve the problem. Check the Jasmine introduction for how to do this.

jQuery event to trigger action when a div is made visible

I'm using jQuery in my site and I would like to trigger certain actions when a certain div is made visible.
Is it possible to attach some sort of "isvisible" event handler to arbitrary divs and have certain code run when they the div is made visible?
I would like something like the following pseudocode:
$(function() {
$('#contentDiv').isvisible(function() {
alert("do something");
});
});
The alert("do something") code should not fire until the contentDiv is actually made visible.
Thanks.

You could always add to the original .show() method so you don't have to trigger events every time you show something or if you need it to work with legacy code:
Jquery extension:
jQuery(function($) {
var _oldShow = $.fn.show;
$.fn.show = function(speed, oldCallback) {
return $(this).each(function() {
var obj = $(this),
newCallback = function() {
if ($.isFunction(oldCallback)) {
oldCallback.apply(obj);
}
obj.trigger('afterShow');
};
// you can trigger a before show if you want
obj.trigger('beforeShow');
// now use the old function to show the element passing the new callback
_oldShow.apply(obj, [speed, newCallback]);
});
}
});
Usage example:
jQuery(function($) {
$('#test')
.bind('beforeShow', function() {
alert('beforeShow');
})
.bind('afterShow', function() {
alert('afterShow');
})
.show(1000, function() {
alert('in show callback');
})
.show();
});
This effectively lets you do something beforeShow and afterShow while still executing the normal behavior of the original .show() method.
You could also create another method so you don't have to override the original .show() method.

The problem is being addressed by DOM mutation observers. They allow you to bind an observer (a function) to events of changing content, text or attributes of dom elements.
With the release of IE11, all major browsers support this feature, check http://caniuse.com/mutationobserver
The example code is a follows:
$(function() {
$('#show').click(function() {
$('#testdiv').show();
});
var observer = new MutationObserver(function(mutations) {
alert('Attributes changed!');
});
var target = document.querySelector('#testdiv');
observer.observe(target, {
attributes: true
});
});
<div id="testdiv" style="display:none;">hidden</div>
<button id="show">Show hidden div</button>
<script type="text/javascript" src="https://code.jquery.com/jquery-1.9.1.min.js"></script>

There is no native event you can hook into for this however you can trigger an event from your script after you have made the div visible using the .trigger function
e.g
//declare event to run when div is visible
function isVisible(){
//do something
}
//hookup the event
$('#someDivId').bind('isVisible', isVisible);
//show div and trigger custom event in callback when div is visible
$('#someDivId').show('slow', function(){
$(this).trigger('isVisible');
});

You can use jQuery's Live Query plugin.
And write code as follows:
$('#contentDiv:visible').livequery(function() {
alert("do something");
});
Then everytime the contentDiv is visible, "do something" will be alerted!

redsquare's solution is the right answer.
But as an IN-THEORY solution you can write a function which is selecting the elements classed by .visibilityCheck (not all visible elements) and check their visibility property value; if true then do something.
Afterward, the function should be performed periodically using the setInterval() function. You can stop the timer using the clearInterval() upon successful call-out.
Here's an example:
function foo() {
$('.visibilityCheck').each(function() {
if ($(this).is(':visible')){
// do something
}
});
}
window.setInterval(foo, 100);
You can also perform some performance improvements on it, however, the solution is basically absurd to be used in action. So...

The following code (pulled from http://maximeparmentier.com/2012/11/06/bind-show-hide-events-with-jquery/) will enable you to use $('#someDiv').on('show', someFunc);.
(function ($) {
$.each(['show', 'hide'], function (i, ev) {
var el = $.fn[ev];
$.fn[ev] = function () {
this.trigger(ev);
return el.apply(this, arguments);
};
});
})(jQuery);

If you want to trigger the event on all elements (and child elements) that are actually made visible, by $.show, toggle, toggleClass, addClass, or removeClass:
$.each(["show", "toggle", "toggleClass", "addClass", "removeClass"], function(){
var _oldFn = $.fn[this];
$.fn[this] = function(){
var hidden = this.find(":hidden").add(this.filter(":hidden"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function(){
$(this).triggerHandler("show"); //No bubbling
});
return result;
}
});
And now your element:
$("#myLazyUl").bind("show", function(){
alert(this);
});
You could add overrides to additional jQuery functions by adding them to the array at the top (like "attr")

a hide/show event trigger based on Glenns ideea:
removed toggle because it fires show/hide and we don't want 2fires for one event
$(function(){
$.each(["show","hide", "toggleClass", "addClass", "removeClass"], function(){
var _oldFn = $.fn[this];
$.fn[this] = function(){
var hidden = this.find(":hidden").add(this.filter(":hidden"));
var visible = this.find(":visible").add(this.filter(":visible"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function(){
$(this).triggerHandler("show");
});
visible.filter(":hidden").each(function(){
$(this).triggerHandler("hide");
});
return result;
}
});
});

I had this same problem and created a jQuery plugin to solve it for our site.
https://github.com/shaunbowe/jquery.visibilityChanged
Here is how you would use it based on your example:
$('#contentDiv').visibilityChanged(function(element, visible) {
alert("do something");
});

What helped me here is recent ResizeObserver spec polyfill:
const divEl = $('#section60');
const ro = new ResizeObserver(() => {
if (divEl.is(':visible')) {
console.log("it's visible now!");
}
});
ro.observe(divEl[0]);
Note that it's crossbrowser and performant (no polling).

Just bind a trigger with the selector and put the code into the trigger event:
jQuery(function() {
jQuery("#contentDiv:hidden").show().trigger('show');
jQuery('#contentDiv').on('show', function() {
console.log('#contentDiv is now visible');
// your code here
});
});

Use jQuery Waypoints :
$('#contentDiv').waypoint(function() {
alert('do something');
});
Other examples on the site of jQuery Waypoints.

I did a simple setinterval function to achieve this. If element with class div1 is visible, it sets div2 to be visible. I know not a good method, but a simple fix.
setInterval(function(){
if($('.div1').is(':visible')){
$('.div2').show();
}
else {
$('.div2').hide();
}
}, 100);

You can also try jQuery appear plugin as mentioned in parallel thread https://stackoverflow.com/a/3535028/741782

This support easing and trigger event after animation done! [tested on jQuery 2.2.4]
(function ($) {
$.each(['show', 'hide', 'fadeOut', 'fadeIn'], function (i, ev) {
var el = $.fn[ev];
$.fn[ev] = function () {
var result = el.apply(this, arguments);
var _self=this;
result.promise().done(function () {
_self.triggerHandler(ev, [result]);
//console.log(_self);
});
return result;
};
});
})(jQuery);
Inspired By http://viralpatel.net/blogs/jquery-trigger-custom-event-show-hide-element/

There is a jQuery plugin available for watching change in DOM attributes,
https://github.com/darcyclarke/jQuery-Watch-Plugin
The plugin wraps All you need do is bind MutationObserver
You can then use it to watch the div using:
$("#selector").watch('css', function() {
console.log("Visibility: " + this.style.display == 'none'?'hidden':'shown'));
//or any random events
});

Hope this will do the job in simplest manner:
$("#myID").on('show').trigger('displayShow');
$('#myID').off('displayShow').on('displayShow', function(e) {
console.log('This event will be triggered when myID will be visible');
});

I changed the hide/show event trigger from Catalint based on Glenns idea.
My problem was that I have a modular application. I change between modules showing and hiding divs parents. Then when I hide a module and show another one, with his method I have a visible delay when I change between modules. I only need sometimes to liten this event, and in some special childs. So I decided to notify only the childs with the class "displayObserver"
$.each(["show", "hide", "toggleClass", "addClass", "removeClass"], function () {
var _oldFn = $.fn[this];
$.fn[this] = function () {
var hidden = this.find(".displayObserver:hidden").add(this.filter(":hidden"));
var visible = this.find(".displayObserver:visible").add(this.filter(":visible"));
var result = _oldFn.apply(this, arguments);
hidden.filter(":visible").each(function () {
$(this).triggerHandler("show");
});
visible.filter(":hidden").each(function () {
$(this).triggerHandler("hide");
});
return result;
}
});
Then when a child wants to listen for "show" or "hide" event I have to add him the class "displayObserver", and when It does not want to continue listen it, I remove him the class
bindDisplayEvent: function () {
$("#child1").addClass("displayObserver");
$("#child1").off("show", this.onParentShow);
$("#child1").on("show", this.onParentShow);
},
bindDisplayEvent: function () {
$("#child1").removeClass("displayObserver");
$("#child1").off("show", this.onParentShow);
},
I wish help

One way to do this.
Works only on visibility changes that are made by css class change, but can be extended to watch for attribute changes too.
var observer = new MutationObserver(function(mutations) {
var clone = $(mutations[0].target).clone();
clone.removeClass();
for(var i = 0; i < mutations.length; i++){
clone.addClass(mutations[i].oldValue);
}
$(document.body).append(clone);
var cloneVisibility = $(clone).is(":visible");
$(clone).remove();
if (cloneVisibility != $(mutations[0].target).is(":visible")){
var visibilityChangedEvent = document.createEvent('Event');
visibilityChangedEvent.initEvent('visibilityChanged', true, true);
mutations[0].target.dispatchEvent(visibilityChangedEvent);
}
});
var targets = $('.ui-collapsible-content');
$.each(targets, function(i,target){
target.addEventListener('visibilityChanged',VisbilityChanedEventHandler});
target.addEventListener('DOMNodeRemovedFromDocument',VisbilityChanedEventHandler });
observer.observe(target, { attributes: true, attributeFilter : ['class'], childList: false, attributeOldValue: true });
});
function VisbilityChanedEventHandler(e){console.log('Kaboom babe'); console.log(e.target); }

my solution:
; (function ($) {
$.each([ "toggle", "show", "hide" ], function( i, name ) {
var cssFn = $.fn[ name ];
$.fn[ name ] = function( speed, easing, callback ) {
if(speed == null || typeof speed === "boolean"){
var ret=cssFn.apply( this, arguments )
$.fn.triggerVisibleEvent.apply(this,arguments)
return ret
}else{
var that=this
var new_callback=function(){
callback.call(this)
$.fn.triggerVisibleEvent.apply(that,arguments)
}
var ret=this.animate( genFx( name, true ), speed, easing, new_callback )
return ret
}
};
});
$.fn.triggerVisibleEvent=function(){
this.each(function(){
if($(this).is(':visible')){
$(this).trigger('visible')
$(this).find('[data-trigger-visible-event]').triggerVisibleEvent()
}
})
}
})(jQuery);
example usage:
if(!$info_center.is(':visible')){
$info_center.attr('data-trigger-visible-event','true').one('visible',processMoreLessButton)
}else{
processMoreLessButton()
}
function processMoreLessButton(){
//some logic
}

$( window ).scroll(function(e,i) {
win_top = $( window ).scrollTop();
win_bottom = $( window ).height() + win_top;
//console.log( win_top,win_bottom );
$('.onvisible').each(function()
{
t = $(this).offset().top;
b = t + $(this).height();
if( t > win_top && b < win_bottom )
alert("do something");
});
});

$(function() {
$(document).click(function (){
if ($('#contentDiv').is(':visible')) {
alert("Visible");
} else {
alert("Hidden");
}
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="contentDiv">Test I'm here</div>
<button onclick="$('#contentDiv').toggle();">Toggle the div</button>

<div id="welcometo">Özhan</div>
<input type="button" name="ooo"
onclick="JavaScript:
if(document.all.welcometo.style.display=='none') {
document.all.welcometo.style.display='';
} else {
document.all.welcometo.style.display='none';
}">
This code auto control not required query visible or unvisible control