Develop Reference

Turn on() event back after apply off

How can I turn an on('click') event back on after I apply event off()?
$('#btn-aluno').on('click', function() {
$('.new-step-email-aluno').toggle();
$('#btn-familiar').off();
});
$('#btn-familiar').on('click', function() {
$('.new-step-email-familiar').toggle();
$('#btn-aluno').off();
});
new-step-email-familiar and new-step-email-aluno = <input>
btn-aluno and btn-familiar = <span> (used as a button)

Instead of turning off the event listener, you could do the same thing by using event delegation,
$(document).on('click',"#btn-aluno.active", function() {
$('.new-step-email-aluno').toggle();
$('#btn-familiar').removeClass("active");
});
$(document).on('click',"#btn-familiar.active", function() {
$('.new-step-email-familiar').toggle();
$('#btn-aluno').removeClass("active");
});
And whenever you want to activate the event listeners, just add the class active to the relevant elements. Also in the place of document try to use any closest static parent of the element on which the event gonna be bound.
As per your requirement, you have edit your logic like below,
$(document).on('click',"#btn-aluno.active", function() {
$('.new-step-email-aluno').toggle();
$('#btn-familiar').toggleClass("active");
});
$(document).on('click',"#btn-familiar.active", function() {
$('.new-step-email-familiar').toggle();
$('#btn-aluno').toggleClass("active");
});
DEMO

I'm trying to attach events using on() based on changing selectors

I have a button that can be in 2 different states (lets say Lock and Unlock). When I click on the button, I update the class on the button to reflect the binary opposite state. Each class has a different event attachment function using on(string, callback). For some reason the event being triggered remains the first callback assigned based on the original class.
HTML:
<button class="lock">Lock</button>
<button class="unlock">Unlock</button>
JavaScript:
$(document).ready(function() {
$('.lock').on('click', function() {
// Perform some magic here
console.log('Lock!');
$(this).removeClass('lock')
.addClass('unlock')
.html('Unlock');
});
$('.unlock').on('click', function() {
// Perform some magic here
console.log('Unlock!');
$(this).removeClass('unlock')
.addClass('lock')
.html('Lock');
});
});
https://jsfiddle.net/c283uaog/ for testing.
Expected console output when clicking on the same button repeatedly:
Lock!
Unlock!
Lock!
Actual console output:
Lock!
Lock!
Lock!
Any assistance would be greatly desired

use event Delegation
$(document).on('click','.lock', function() {
$(document).on('click','.unlock', function() {
updated Demo
Or use in single function with toggleClass
$(document).on('click', '.lock,.unlock', function () {
$('#output').html($(this).attr('class'));
$(this).toggleClass('lock unlock').text($(this).attr('class'));
});
ToggleClass demo

I'd do it this way, attaching only one event: http://jsfiddle.net/jozu47tv/
$(".lock").on('click', function(e) {
e.preventDefault();
if($(this).hasClass("lock")) {
$(this).removeClass("lock").addClass("unlock");
console.log("lock -> unlock");
} else {
$(this).removeClass("unlock").addClass("lock");
console.log("unlock -> lock");
}
})

Use Event Delegation method, Try this updated fiddle,
$(document).ready(function() {
$(document).on('click', '.lock', function() {
$('#output').html('Lock!');
$(this).removeClass('lock')
.addClass('unlock')
.html('Unlock');
});
$(document).on('click', '.unlock', function() {
$('#output').html('Unlock!');
$(this).removeClass('unlock')
.addClass('lock')
.html('Lock');
});
});

Probably, this question could answer you in a better way:
jQuery .on function for future elements, as .live is deprecated
$(document).on(event, selector, handler)

Change your html to this:
<button class="locker lock" >Lock</button>
<button class="locker unlock"">Unlock</button>
<div id="output">Output</div>
and your Js to this:
$(document).ready(function() {
$('.locker').on('click', function() {
if($(this).hasClass("lock")){
$(this).removeClass("lock");
$(this).addClass("unlock");
$(this).html("unlock");
}
else if($(this).hasClass("unlock")){
$(this).removeClass("unlock");
$(this).addClass("lock");
$(this).html("lock");
}
});
});

Adding an on event to an e.currentTarget?

A variety of elements on my page have the content editable tag.
When they are clicked I do this:
$('[contenteditable]').on('click', this.edit);
p.edit = function(e) {
console.log(e.currentTarget);
e.currentTarget.on('keydown', function() {
alert("keydown...");
});
};
I get the current target ok, but when I try to add keydown to it, I get the err:
Uncaught TypeError: undefined is not a function

It's a native DOM element, you'll have to wrap it in jQuery
$(e.currentTarget).on('keydown', function() {
alert("keydown...");
});
e.currentTarget should equal this inside the event handler, which is more commonly used ?
It's a little hard to tell how this works, but I think I would do something like
$('[contenteditable]').on({
click : function() {
$(this).data('clicked', true);
},
keydown: function() {
if ($(this).data('clicked'))
alert("keydown...");
}
});
Demo

First issue is you are trying to use jQuery methods on a DOM element. Second issue is I do not think you want to bind what is clicked on, but the content editable element itself.
It also seems weird to be adding the event on click instead of a global listener. But this is the basic idea
$(this) //current content editable element
.off("keydown.cust") //remove any events that may have been added before
.on('keydown.cust', function(e) { //add new event listener [namespaced]
console.log("keydown"); //log it was pressed
});

Edited: I had a fail in code. It works fine now.
Getting your code, I improved to this one:
$(function(){
$('[contenteditable]').on('click', function(){
p.edit($(this));
});
});
var p = {
edit: function($e) {
console.log($e);
$e.on('keydown', function() {
console.log($(this));
alert("keydown...");
});
}
}
You can check it at jsFiddle

You need to wrap the e.currentTarget(which is a native DOM element) in jQuery since "on" event is a jQuery event:
$(e.currentTarget).on('keydown', function() {
alert("keydown...");
});
EDIT:
$('[contenteditable]').on('click', p.edit);
p.edit = function(e) {
$(e.currentTarget).on('keydown', function() {
alert("keydown...");
});
};
You're defining p.edit AFTER $('[contenteditable]').on('click', p.edit); resulting in an error since p.edit doesn't exist when declaring the on.
In case you don't know, you are defining p.edit as a function expression, meaning that you have to define it BEFORE calling it.

Prevent element from animating based on previous class

$('.example').hover(
function () {
$(this).css('background','red');
},
function () {
$(this).css('background','yellow');
}
);
$('.test').click(function(){
$(this).css('marginTop','+=20px').removeClass('example');
}
);
<div class="text example"></div>
Although the class example was seemingly removed, the hover actions for it are still being applied to the element that once had that class. How can I prevent this?
http://jsfiddle.net/gSfc3/
Here it is in jsFiddle. As you can see, after executing the click function to remove the class, the background still changes on hover.

Event handlers are bound to a Node, so it doesn't matter if that Node doesn't own a specific className anymore. You would need to .unbind() those events manually, or better, use jQuerys .off() method.
So, if you can be sure that there aren't any other event handlers bound to that node, just call
$(this).css('marginTop','+=20px').removeClass('example').off();
This will remove any event handler from that Node. If you need to be specific, you can use jQuerys Event namespacing, like so
$('.example').on( 'mouseenter.myNamespace'
function () {
$(this).css('background','red');
}
).on('mouseleave.myNamespace'
function() {
$(this).css('background','yellow');
}
);
and use this call to only unbind any event that is within the namespace .myNamespace
$(this).css('marginTop','+=20px').removeClass('example').off('.myNamespace');

$('.example').unbind('mouseenter').unbind('mouseleave')
In your code, $('.example').hover attaches a mouseenter and mouseleave directly to each element.
-or-
A better solution might be to use delegation with on
$(document.body).on('mouseenter', '.example', function() { ... });
$(document.body).on('mouseleave', '.example', function() { ... });
Using that code, removing the example class will work as expected, because the handlers are based on css selector, while .hover attaches directly to the elements.

$('.example').live({
mouseenter:function () {
$(this).css('background','red');
},
mouseleave:function () {
$(this).css('background','yellow');
}
});
demo: http://jsfiddle.net/gSfc3/1/

Try this:
$('.test').hover(
function () {
$('.example').css('background','red');
},
function () {
$('.example').css('background','yellow');
}
);

jQuery unbind click event function and re-attach depending on situation

The code below I use to create a sliding menu. I need to know how to unbind the function attached to the click event and re-attach it some other time. (using jQuery 1.7.2)
$(document).ready(function(){
$('.section').hide();
$('.header').click(function(){
if($(this).next('.section').is(':visible'))
{
$('.section:visible').slideUp()
$('.arrows:visible').attr("src","right.gif")
}
else
{
$('.section').slideUp();
$(this).next('.section').slideToggle();
$(this).find('.arrows').attr("src","down.gif")
});
});
The code below is what I have so far
$('#printVers').click(function(){
if($('#formVersion').val() != "Print")
{
$('.header').unbind('click');
}
else
{
//else re-attach functionality?
}
});
Thanks

Simply make a named function. You can go low tech here and back to basics to unbind and reattach specific events.
function doStuff()
{
if($(this).,next('.section').is(':visible'))
...
}
$('.header').on('click', doStuff);
$('.header').off('click', doStuff);

Instead of unbind and re-bind, I suggest you to add a simple class to .header and check for the class in the click handler. See below,
$('#printVers').click(function(){
if($('#formVersion').val() != "Print")
{
$('.header').addClass('dontClick');
} else {
$('.header').removeClass('dontClick');
}
});
And in your .header click handler,
$('.header').click(function(){
if ($(this).hasClass('dontClick')) {
return false;
}
//rest of your code
If you insist on having a unbind and bind, then you can move the handler to a function and unbind/bind the function any number of time..

You can try something like this.
$('#printVers').click(function(){
if($('#formVersion').val() != "Print")
{
$('.header').addClass('clickDisabled');
}
else
{
$('.header').removeClass('clickDisabled');
}
});
And then in the click handler check for this class.
$(document).ready(function(){
$('.section').hide();
$('.header').click(function(){
if(!$(this).hasClass('clickDisabled')){
...
...
}
});
});

Why not make that top section a function, and then call it in your else statement?

You could try setting a variable as a flag. var canClick = ($('#formVersion').val() != 'Print'); Then in the click handler for your .header elements check to see if canClick is true before executing your code.
If you still want to remove the handler you can assign the events object to a variable. var eventObj = #('.header').data('events'); That will give you an object with all the handlers assigned to that object. To reassign the click event it would be like $('.header').bind('click', eventObj.click[0]);

After trying so hard with bind, unbind, on, off, click, attr, removeAttr, prop I made it work.
So, I have the following scenario: In my html i have NOT attached any inline onclick handlers.
Then in my Javascript i used the following to add an inline onclick handler:
$(element).attr('onclick','myFunction()');
To remove this at a later point from Javascript I used the following:
$(element).prop('onclick',null);
This is the way it worked for me to bind and unbind click events dinamically in Javascript. Remember NOT to insert any inline onclick handler in your elements.

You could put all the code under the .click in a separated function
function headerClick(){
if($(this).next('.section').is(':visible'))
{
$('.section:visible').slideUp()
$('.arrows:visible').attr("src","right.gif")
}
else
{
$('.section').slideUp();
$(this).next('.section').slideToggle();
$(this).find('.arrows').attr("src","down.gif")
}
}
and then bind it like this:
$(document).ready(function(){
$('.section').hide();
$('.header').click(headerClick);
});
$('#printVers').click(function(){
if($('#formVersion').val() != "Print")
{
$('.header').unbind('click');
}
else
{
$('.header').click(headerClick);
}
});