Develop Reference

Is there a way to apply jQuery to dynamically created elements? (not event listeners)

I have dynamically created an element with the following class:
<span class="text">Hello</span>
and jQuery:
function changeText() {
var oldText = $(this).text();
$(this).text(oldText + " There");
}
$(function() {
$(".text").each(function(){
changeText.apply(this);
})
})
Obviously, this is a simplified version of what is actually happening but the basics are there. Is it possible to apply this rule to dynamically created elements even though we are not using event listeners?
The problem here is that there is no specific location for these ".text" elements. The only place we know these will show up is in the body. I we use a mutationObserver on the body... wouldn't that be taxing performance?

Do this instead:
function changeText() {
var oldText = $(this).text();
$(this).text(oldText + ' There');
}
$(function(){
$('.text').each(function(i, e){
changeText.call(e);
});
});

Like this
$dynamicElement.find(".text").each(function(){
changeText.apply(this);
})

How do I replace a div after dropdown selection?

All I need is to replace the form with class="simple_form calculation" when the jQuery dropdown has been selected. Here is my jQuery.
Can I use a .replaceAll for this?
$("#role_selector_for_questions").change(function(e) {
var $dropdown = $(this);
$.get('/calculations/role/' + $dropdown.val(), function(data) {
$dropdown.after(data);
});
});

Do you need to change the class of a form element
if so you can use jQuery .removeClass to remove current class and jQuery .addClass to add new class.
$("#role_selector_for_questions").change(function(e) {
var $dropdown = $(this);
$('yourformid').removeClass('old_form_class');
$('yourformid').addClass('simple_form calculation');
$.get('/calculations/role/' + $dropdown.val(), function(data) {
$dropdown.after(data);
});
});

I don't see where your 'form' element is defined, but changing a class on the form is as simple as using removeClass() and addClass().
$('#formToAddClass').removeClass('current_class').addClass('simple_form calculation');
BTW, looks like two classes are being added here - 'simple_form' and 'calculation'. Class names do not contain spaces.

$("#role_selector_for_questions").change(function(e) {
var $dropdown = $(this);
$.get('/calculations/role/' + $dropdown.val(), function(data) {
$("#role_selector_for_questison").replaceWith( "<div></div>" );
});
});

click event not working when changing id or class

I'm starting with jquery, and have an issue here:
http://jsfiddle.net/8guzD/
$('#test.off').click(function(){
$(this).removeClass('off').addClass('on');
});
$('#test.on').click(function(){
$(this).removeClass('on').addClass('off');
alert('ok');
});
the first part of the code goes well, the class is apply, but when I attach an event in this element with its new class it won't work.
Can someone explain me what is the problem exactly?
I tried with javascript,
http://jsfiddle.net/R5NRz/
var element = document.getElementById('test');
element.addEventListener('click', function() {
this.id ='test2';
alert("ok");
}, false);
var element2 = document.getElementById('test2');
element2.addEventListener('click', function() {
alert("ok2");
}, false);
and it didn't really help me, having the same issue

try
$(document).on("click",'#test.on',function(){
$(this).removeClass('off').addClass('on');
alert('ok');
});
$(document).on("click",'#test.off',function(){
$(this).removeClass('off').addClass('on');
alert('ok passs');
});
Demo

In your jQuery example you are binding to DOM elements that exist at that time. That is why you see the first fire but not the second. It is not a match for your '#test.on' selector when the code is run. What you want to do instead is use delegation:
$('#test').on('click',function() {
var ele = $(this);
if (ele.hasClass('on')) {
ele.removeClass('on').addClass('off');
} else {
ele.removeClass('off').addClass('on');
}
});
This assumes that you are doing more than just toggling classes. If you want simply toggle classes then an easier solution is to pick one as the default and use the other as a flag. For example, .on is on but without .on it's off. Then you can just use toggle:
$('#test').on('click', function() {
$(this).toggleClass('on');
});

$("#test.on")
Doesn't bind to anything. Try this:
$('#test').click(function() {
if($(this)).hasClass('off') $(this).removeClass('off').addClass('on');
else $(this).removeClass('on').addClass('off');
});
You might consider using an 'active' class instead and just toggling that, instead of have two separate on/off classes. Then you can write:
$("#test").click(function() {
$(this).toggleClass('active');
});

jQuery: Moving element to another element and back again renders the element unclickable

In my script, I'm attempting to move an element (list) from one parent (just the text) to another and then back again (to the list). The problem is that when I have moved the element back to the original parent (ul), it has become un-clickable. I thought using the detach() over the remove() might do the trick but it doesn't make a difference.
$(document).ready(function() {
$("#inventoryWeapon li").click(function(event) {
var clickedId = event.target.id;
if ($("td#weapon").is(":empty")) {
$("td#weapon").text(clickedId);
$(this).detach();
}
});
$("td#weapon").click(function(event) {
var unequipping = $(this).text();
$("#inventoryWeapon").append("<li id='" + unequipping + "'>" + unequipping + "</li>");
$(this).detach();
});
});

As suggested in the popular comment above, you are not moving the element. To move it, do this.
$("td#weapon").click(function(event) {
$(this).appendTo($("#inventoryWeapon"));
});

You're not moving the element, you're removing the element in one function, and creating a new element with the same ID and content in the other. But the original event handler was only bound to the original element.
If you want your event handler to work with dynamically created elements, use event delegation:
$("#inventoryWeapon").on("click", "li", function(event) {
...
});
Alternatively, you could save the element when you detach it, instead of recreating it:
var savedLI;
$("#inventoryWeapon li").click(function() {
if ($("td#weapon").is(":empty")) {
savedLI = $(this).detach();
$("td#weapon").text(this.id);
}
});
$("td#weapon").click(function() {
if (savedLI) {
$("#inventoryWeapon").append(savedLI);
$(this).detach();
}
});

How to dynamically add html elements with jquery?

My goal is to have one element on initial load, this element should have id="something_O", when a add link is clicked, underneath already existing element, new, the same html element should be added,not with id="something_o", but with id="something_1", or last element + 1, to be specific. The user should be able to add these elements infinitely. When the user clicks deleted, element should disappear.
Any ideas?
Here is prepared fiddle for easier help...

var counter = 1;
$('.AddEl').live('click', function () {
var el = $('#element_1').clone().attr('id', 'element_' + ++counter).appendTo('body');
});
$('.RemoveEl').live('click', function () {
var el = $(this).parents('.elem')
if (el.get(0).id !== 'element_1') el.remove();
});
Check this here

One means to do this is:
$(document).ready(function() {
$('body').on('click', '.AddEl', function() {
$('.actions:first')
.parent()
.clone()
.attr('id', 'element_' + $('.actions').length)
.insertAfter($('.actions:last').parent());
});
$('body').on('click', '.RemoveEl', function() {
$(this).closest('.actions').parent().remove();
});
});
JS Fiddle demo.
Please note that I've amended your html so that the first element to be cloned is now id="element_0", and targeted that, and all subsequently-created elements, with the CSS selector:
div[id^=element] {
/* css */
}
This could be simplified, but these are simply my first thoughts.
Edited to offer a slightly improved version, in that the initial addition is slightly, or seems a little, more concise, and also features a means to prevent duplicate ids being generated if elements are added/removed:
$(document).ready(function() {
$('body').on('click', '.AddEl', function() {
var $elems = $('.actions').parent();
$elems
.first()
.clone()
.insertAfter($elems.last());
$('div[id^="element_"]').each(
function(i){
$(this).attr('id','element_' + i);
});
});
$('body').on('click', '.RemoveEl', function() {
$(this).closest('.actions').parent().remove();
});
});
JS Fiddle demo.

I just overwrite to your code.
You can try this, may something you want.
http://jsfiddle.net/kongkannika/QeSPP/34/