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JQuery select elements in <span> that doesn't exist initially

I've been looking for so long and found several answers that suggest using .on() as in $('.idOfMyElemenet').on() works even for elements that don't exist yet. But this doesn't seem to be finding the element. Am I doing something wrong?
The highest level <span> (in screenshot) does not exist until I click on a drop-down. Ultimately I'm trying to trigger an event when the user clicks on any of the <li> (aka selects an option from the drop-down).
$(document).ready(function () {
var test = "#select2-id_customer-results";
$(test).on("click", function() {
console.log('hello')
})
})
EDIT:
Thanks to Drew Baker - I think his second solution is the way to go. But not quite there yet...
From the select2 documentation
All public events are relayed using the jQuery event system, and they
are triggered on the <select> element that Select2 is attached to.
So I tried listening to it via the id (which doesn't seem to exist but would probably be id_customer) and the class. The class I added below did not work. Is there a way to listen to this using Jquery?
$(document).ready(function () {
// console.log($('#id_customer'));
$('.modelselect2 form-control select2-hidden-accessible').on('select2:select', function (e) {
var data = e.params.data;
console.log(data);
});
});

I'll answer your question, but then give you a better solution.
First, you need to make sure the thing you are attaching .on() to actually exists. I typically use a containing DIV or failing that body or html will work.
Secondly you are missing a parameter that tells jQuery the thing you are looking to watch to be clicked on. In this case, I'm assuming it is the UL tag with the ID you provided.
This should do what you want:
$(document).ready(function () {
$('body').on("click", "#select2-id_customer-results", function() {
console.log('hello')
})
})
But a better solution would be to use the Select2 API to have it tell you when something is selected. This will be way more reliable and should make your code work after upgrades to Select2.
Something like this:
$('select[name="customer"]').on('select2:select', function (e) {
var data = e.params.data;
console.log(data);
});
NOTE: #mySelect2 is probably not what you have. Use whatever ID you used to initialize Select2 in jQuery.
You can read more about that API here: https://select2.org/programmatic-control/events

if your element is dynamically generated and you want to target that specific element. You need to specify a static container/parent element to indicate where it belongs.
Try this:
$( '#dynamicallyAddedElement' ).on( 'click', '#wrapper', function () { ... });
//where #wrapper is a static parent element in which you add the dynamic links.
So, you have a wrapper which is hard-coded into the HTML source code:
PS. Hope I helped in some way.

If you need to trigger an event when click on <li> elements, you have to use that elements id or class as the selector. Check the below code:
$(document).ready(function () {
var test = ".select2-results__option";
$(test).on("click", function() {
console.log('hello')
})
})

It turns out this is an old bug in django-auto-complete.
The code below works. I have no idea why but now I can move on.
Note: the 'name' is the value of the select2 select element (see screenshot at bottom)
document.querySelector('select[name="customer"]').onchange=function() {
console.log("myselect2name changed");
};

Dojo delegate to DOM Element's ID

I am working with a JSP that dynamically includes DOM elements such as a buttons based on a user's privilege or other factors.
Now, in my JS, I was using:
dojo.connect(dojo.byId('dispatchBtn'), 'onclick', function() { //logic }
The problem is, if the 'dispatchBtn' doesn't exist because it was stripped based on the user's privilege, the JS just calls all the contents of the "//logic" anyway.
I tried to change this call to:
eventView.delegate(dojo.byId('dispatchBtn'), 'onclick', function() { //logic }
But that doesn't seem to work at all, even for buttons that DO exist. What's the best way to do this without explicitly testing if the button exists. I do not want to change the markup on any of these button elements, no additional classes, just want to reference them by ID.

You can do like jquery live does and bind on the document level.
require(["dojo/on", "dojo/query"], function(on){
on(document, "#dispatchBtn:click", function(evt){
alert("Clicked on node " + this.id);
});
});
Fiddle:http://jsfiddle.net/theinnkeeper/NTn6g/

Why are you adverse to checking if the button exists? That makes the most sense
var btn = dojo.byId("dispatchBtn");
if(btn) {
on(btn, 'onclick', function() {});
}

jquery .live() and .append()

So I'm currently using .append() to add a feature to all of the posts on a webpage, but when additional posts are loaded on the page, the appended features aren't included in the new content — I'm trying to come up with a way to make sure all of the new content has the appended feature too.
$(this).append('<div id="new_feature></div>');
Something like this?
$(this).live().append('<div id="new_feature></div>');
Maybe there's a way to make it constantly appending in a loop perhaps?

There is DOMNodeInserted event:
$('button').click(function() {
$('#appendme').append($('<div class="inner">').text(Math.random()));
})
$('#appendme').on('DOMNodeInserted','.inner',function() {
console.log(this);
});
DEMO
update: this seems not works in IE, try propertychnage event handler also ($('#appendme').on('DOMNodeInserted,propertychange') but i not sure, have no IE to check this right now.
update2: Domnode* seems deprecated according to mdn, they tell to use MutationObserver object instead
update3: seems here is no very crossbrowser solution for MutationEvents, see this answer, so my suggestion would be use code above, if event supported and fallback to setTimeOut or livequery option.
update4:
If you depend only on .append() you can patch jQuery.fn.append() like this:
jQuery.fn.append=function() {
return this.domManip(arguments, true, function( elem ) {
if ( this.nodeType === 1 || this.nodeType === 11 ) {
this.appendChild( elem );
$(elem).trigger('appended');
}
});
};
$('button').click(function() {
$('#appendme').append($('<div class="inner">').text(Math.random()));
})
$('#appendme').on('appended','.inner',function() {
console.log(this);
});
DEMO2
may be more correct is to spoof jQuery.fn.domManip like here

jQuery documentation:
Use of the .live() method is no longer recommended since later versions of jQuery offer better methods that do not have its drawbacks.
You can use setTimeout() function that can check for new <div>s every n milliseconds.
$(function(){
setInterval("Check4NewDivs();",1000);
});
So say this is a div with class="comment newdiv", so when it appears on the page for the first time, it has the class newdiv that will let the function know it was just dynamically created.
function Check4NewDivs(){
$(".comment .newdiv").each(function(){
$(this).append('<div class="new_feature"></div>').removeClass("newdiv");
});
}

It's append not appened.
live is a deprecated event handler. It's not used this way. use on instead.
http://api.jquery.com/live/
So, the following code will run when you click selector.
$(document).on('click', 'selector', function() {
$(this).append('<div id="new_feature></div>');
});

No, there is no standard way to do it like that. There was a proposal of the events that would be fired whenever the DOM elements are inserted etc., but you cannot rely on that.
Instead rely on either:
(preferably) callbacks - just invoke function ensuring existence of such appended snippets, whenever you pull something (but after you successfully pull it from server and insert into DOM, not sooner), or
constant checks - like using in setInterval() or setTimeout(), but this would be unnecessary processing and you will never get instant append, unless you will perform processing-heavy checks all the time,

use the on load function:
$(item).on('load',function(){
$(this).append('<div id="new_feature"></div>');
});
This will add append the item as a callback once the item has been loaded. I would also choose some sort of dynamic ID creator rather than always append stuff with the same ID, but thats just me.

you must bind to an element that already exists on the page. i have written an example where i make appended content live.
DEMO on JSFiddle
HTML
<div id="container">
<div id="features">
</div>
<br />
<a href='#' id='clickme'>click me to add feature</a>
</div>
JS
$(function() {
$('#clickme').on('click', function(e) {
$('#features').append('<div class="new_feature">new feature</div>');
});
$('#features').on('click', '.new_feature', function() {
alert('i am live.');
});
});

not work class .numeric after add new input. what do i do?

why after add new input, class .numeric (normal number formatting) in js code not worked?
This way for normal number formatting is right?
What is your suggestion?
i not want use of plugin.
DEMO
$("input:text.numeric").keyup(function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
})
With respect

If you add something to the page after it is done loading you will need to use the live() function on your scripts to make them work on the new data.
If you do something like:
$('#container').append('<div class="clickme">The text goes here</div>');
or
$('#container').load('script.php');
...they are both considered adding to the page.
Using live(), your code would become:
$("input:text.numeric").live('keyup', function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
});
Read more here: http://api.jquery.com/live/

You need a future-proof event observer. Since the keyup bind is assigned to existing nodes, any nodes you create afterwards will not be bound to that event. You need to use live or delegate
Change
$("input:text.numeric").keyup(function () {
to
$("input:text.numeric").live('keyup',function () {
or
$('.find_input').delegate('input:text.numeric','keyup',function () {
delegate() is much more resource-friendly than live() but you need to know the parent ahead of time. In your example, I'd recommend it.
Working demo: http://jsfiddle.net/AlienWebguy/zgWr3/4/

Use the delegate()[docs] method to bind the handler to the .column container.
Example: http://jsfiddle.net/zgWr3/3/
$('.column').delegate("input.numeric:text",'keyup',function () {
$val = $(this).val().match(/[0-9]/g).reverse().join("").match(/[0-9]{1,3}/g).join(",").match(/./g).reverse().join("");
$(this).val($val)
});
This way, any "input.numeric:text" elements inside of .column will invoke the handler irrespective of when they're added to the DOM.
I also changed the selector around a little. Seems more understandable to me.

Loop over elements in jQuery when element is double clicked

I'm new to jQuery and Javascript. I'm trying to make a button that I can double click which then loops through all elements in the webpage with a certain class and fades them.
Currently, I'm trying this:
$(".fadeall").dblclick(function() {
$("div.section").each(function(idx,item) {
item.fadeTo(25,inactiveOpacity);
});
});
In my debugger I see the double click happening, but the function in the each call is not being triggered.
I'm believe I'm not matching the div.section elements correctly, but don't know the correct approach.

It should be erroring out since the DOM element doesn't have a .fadeTo() function, you need to wrap the element you're looping over (item) in a jQuery object, like this:
$(item).fadeTo(25,inactiveOpacity);
Or, this works as well, for example:
$(".fadeall").dblclick(function() {
$("div.section").each(function() {
$(this).fadeTo(25,inactiveOpacity);
});
});

Assuming the HTML has <div> elements with the class section, the only other thing I can see that you would need to do is wrap item in a jQuery object.
$(".fadeall").dblclick(function() {
$("div.section").each(function(idx,item) {
// Wrapped "item" so you have access to jQuery methods
$(item).fadeTo(25,inactiveOpacity);
});
});
Since item is the DOM element, it needs to be wrapped with a jQuery object so that it will have access to methods like .fadeTo().
Another approach is to use this in the .each(), which will refer to the DOM element as well.
$(".fadeall").dblclick(function() {
$("div.section").each(function() {
// Wrapped "this" so you have access to jQuery methods
$(this).fadeTo(25,inactiveOpacity);
});
});
EDIT:
Also, make sure the DOM is loaded before your code runs:
// Wrapping code like this ensures that the DOM elements will be
// loaded before your code runs.
$(function() {
$(".fadeall").dblclick(function() {
$("div.section").each(function() {
// Wrapped "this" so you have access to jQuery methods
$(this).fadeTo(25,inactiveOpacity);
});
});
});
This is a shortcut for jQuery's .ready() method, which will ensure that your code doesn't run until the elements are available.