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Executing an action only once - without disable or one click [duplicate]

I want to check if an element has the class .active, if it does add: margin-top: 4px;
However I only want this to occur once, when the page loads, once the class has been detected I don't want to detect it again and add the CSS style.
This class is applied when certain elements are hovered over.
Is this possible in jQuery?

Check out the one event. Documented example:
$('#foo').one('click', function() {
alert('This will be displayed only once.');
});

This will fire once on page load
$(function(){
if ($("#elementid").hasClass("active"))
{
$("#elementid").css("margin-top", "4px");
}
});

The way I usually do this is:
(function($) {
// my custom function to process elements
function myProcessFunction(context) {
// get context
context = context || document;
// select elements within the context, filter out already processed ones
// loop through remained (unprocessed) elements
// '.my-class' - selector for the elements I want to process
$('.my-class:not(.my-class-processed)', context).each( function(i.e){
// mark the element as processed
$(e).addClass('my-class-processed');
// add process code here
});
}
// run myProcessFunction on document.ready
$(document).ready( function(){
myProcessFunction();
});
})(jQuery);
This way I have:
reusable function
processed elements are marked and won't be processed next time the function is called
elements are processed within the context only, if specified (for instance, HTML code returned via an AJAX request)
Hope this helps )

Passing "this" to a function in jQuery problems

sorry but couldn't find a solution for my problem so far.
I am writing a kind of an email template editor as a little task for my boss.
$('a, span').click(function(event){
var editableElement = $(this);
if($(this).is('a')){
event.preventDefault();
}
if(editableElement.is('span')){
processType(editableElement, 'simpleText', modalContent)
When I send the 'editableElement' variable first time, everything's fine, sends object to my function, where I open up a modal window, where there is a textarea, which if i enter text and submit it using only jQuery it will put the text from the textarea (using .val()) to my desired element, in this case a "span" element which is the 'editableElement' using .text() on it. No problem, it works for the first time. After I try to edit a second span, it constantly modifies the previous span too, with whatever I enter in to the textarea (which is cleared out completely, the problem is NOT here) I've ran a fast debug with a simple foreach on the editable element, and the problem is that for some reason it keeps adding objects to the editableElement variable everytime I send it to the function. The number of spans I try to edit, the number of objects will be in my variable all with the index of 0.
Any idea what could be the cause of this?
Thanks in advance!
EDIT:
As requested the whole code in one piece which I have problem with, though it was the whole code before too, I'm in an early stage of writing it, I understand that it was hard to read though, perhaps now it is properly formatted as requested.
$(window).load(function()
{
var modalContent = $('#modalContent');
modalOverlay = $('#modalOverlay');
$('a, span').click(function(event)
{
var editableElement = $(this);
if($(this).is('a'))
{
event.preventDefault();
}
if(editableElement.is('span'))
{
processType(editableElement, 'simpleText', modalContent)
}
});
$('#codeGenButton').click(function()
{
var container = $('#codeContainer');
container.empty();
container.text(getPageHTML());
});
$('#modalClose').click(function()
{
$(this).parent().parent().animate({'opacity': '0'}, 200,
function(){
$(this).css({'display': 'none'});
});
});
});
function fillData(targetDomElement, modalObject)
{
$('#modalSubmit').click(function(){
targetDomElement.text($('#simpleTextEdit').val());
closeModalWindow();
});
}
function processType(targetDomElement, type, modalObject)
{
modalObject.empty();
if(type == 'simpleText')
{
modalObject.append("<p id='simpleTextEditTitle'>Text editor</p><textarea id='simpleTextEdit'></textarea>");
getModalWindow();
fillData(targetDomElement, modalObject);
}
}
Step by step of what it should do:
First of all, the html should not be needed for this, it does not matter, and this is the whole code honestly.
When you click on either an element of (span) or an element of (a) it triggers the function.
It will check if it was actually a (span), or an (a) element.
Currently if it is an element (a), it does nothing, not implemented yet, but if it is a (span), it will call in the processType function, which it sends the "handler?" of the element to namely "editableElement" which has been declared right after the click event, the 'simpleText' which gets send too, is just to differentiate between element types I will send to the processType function later on, and for the last, "modalConotent" is only a div container, nothing more.
Once the function gets the data first, it will make sure, that the modal window gets cleared of ALL data that is inside of it, then it will append a bit of html code as you can see, in to the modal window, which pops up right after I have appended data in to it, it is literally just a 'display: block' and 'animate: opacity: 1' nothing special there.
Lastly it will trigger the 'fillData' function, which will put my desired data from '#simpleTextField' which is only a (textarea) where you can write in, to my desired element 'editableElement' which is the element you have clicked at the first place, a (span) element after the submit, which is again, just a css of 'display: none' and 'opacity: 0' closes the modal window.
THE END.

Your problem is here
function fillData(targetDomElement, modalObject)
{
$('#modalSubmit').click(function(){
targetDomElement.text($('#simpleTextEdit').val());
closeModalWindow();
});
}
Each time this function is called it adds a new click handler with the perameters at the time the handler was created. This handler is added in addition to the already created handlers. See a demo here. After successive clicks on the spans notices how fillData is called multiple times for a single click.
To give you the best possible answer I need to know where your modalSubmit button is in relation to modalContent. Also is is modalSubmit dynamic or static on the page?
Here is a fairly hacky fix in the mean time using on and off to bind and remove the handler respectively:
function fillData(targetDomElement, modalObject)
{
$('#modalSubmit').off("click"); /*Clear Hanlders*/
$('#modalSubmit').on("click", function(){
console.log("fill data");
console.log(targetDomElement);
targetDomElement.text($('#simpleTextEdit').val());
/*closeModalWindow(); Don't have anything for this so ignoring it*/
});
}
Demo

I've solved it myself by using .submit() (of course this means adding form, and an input with the type of submit) instead of .click() when I send the request to modify the element I've clicked on originally.
I don't understand though, why it did what it did when I've used the .click() trigger.

Delegate and AddClass not working

I am having a problem with getting this piece of code to work. Its built to allow for a user to click on one row to "select" it by highlighting via a different class. If another row is clicked, that one is highlighted and the current one is cleared. If one that is already highlighted is clicked again, it will be cleared back to normal.
This is within an ajax call to refresh the page, so everytime the call finishes and inserts the html for the table, this function below is then called. For some reason, every other reload of the table, this works. Ive tracked down the the line that is not functioning to be $(this).addClass(selectedUserClass) at the end of the function. The debug console log I put in there works, with the right class, but the next section does not add the class for some reason.
In firebug, the line changes from .. to , but it doesn't change? I've been looking at this for hours and I can't figure it out. Thanks for any help!
function loadUserListener(style) {
if (style == "normal") {
selectedUserClass = 'selectedUser';
selectedJQueryClass = '.selectedUser';
} else {
selectedUserClass = 'selectedUserInverted';
selectedJQueryClass = '.selectedUserInverted';
}
console.log('setting');
$("#selectuser").delegate("tr", "click", function () {
if ($(this).hasClass(selectedUserClass)) {
$(selectedJQueryClass).removeClass(selectedUserClass);
} else if ($(selectedJQueryClass)[0]) {
console.log('another');
$(selectedJQueryClass).removeClass(selectedUserClass);
$(this).addClass(selectedUserClass);
} else {
console.log(selectedUserClass);
$(this).addClass(selectedUserClass);
}
});
}

adeneo pointed out some things for me, mainly that the listener is still there even though the table is refreshed, so after every ajax call, a listener is being put on another which results in the functionality that only works on 'even' calls.
I used the 'off' function from jquery to clear the event handler every time this listener loading function is called. I also switched delegate to on to be more correct.
I essentially did this:
$('.selectuser').off("click");

Can anyone think of a better way of stopping a user from clicking on anything?

Currenlty when a page is posting back or something else is going on I display a big grey div over the top of the whole page so that the user can't click the same button multiple times. This works fine 99% of the time, the other 1% is on certain mobile devices where the user can scroll/zoom away from the div.
Instead of trying to perfect the CSS so that it works correctly (this will be an on going battle with new devices) I've decided to just stop the user from being able to click anything. Something like $('a').click(function(e){e.preventDefault();}); would stop people from clicking anchor tags and navigating to the link but it wouldn't stop an onclick event in the link from firing.
I want to try to avoid changing the page too radically (like removing every onclick attribute) since the page will eventually have to be changed back to its original state. What I would like to do is intercept clicks before the onclick event is executed but I don't think that this is possible. What I do instead is hide the clicked element on mouse down and show it on mouseup of the document, this stops the click event firing but doesn't look very nice. Can anyone think of a better solution? If not then will this work on every device/browser?
var catchClickHandler = function(){
var $this = $(this);
$this.attr('data-orig-display', $this.css('display'));
$this.css({display:'none'});
};
var resetClickedElems = function(){
$('[data-orig-display]').each(function(){
$(this).css({display:$(this).attr('data-orig-display')}).removeAttr('data-orig-display');
});
};
$('#btn').click(function(){
$('a,input').on('mousedown',catchClickHandler);
$(document).on('mouseup', resetClickedElems);
setTimeout(function(){
$('a,input').off('mousedown',catchClickHandler);
$(document).off('mouseup', resetClickedElems);
}, 5000);
});
JSFiddle: http://jsfiddle.net/d4wzK/2/

You could use the jQuery BlockUI Plugin
http://www.malsup.com/jquery/block/

You can do something like this to prevent all actions of the anchor tags:
jQuery('#btn').click(function(){
jQuery('a').each(function() {
jQuery(this).attr('stopClick', jQuery(this).attr('onclick'))
.removeAttr('onclick')
.click(function(e) {
e.preventDefault();
});
});
});
That renames the onclick to stopclick if you need to revert later and also stops the default behavior of following the href.

document.addListener('click',function(e){e.preventDefault()})
Modified-
Its your duty to remove the click event from the document after you are done accomplishing with your task.
Eg -
function prevent(e){
e.preventDefault()
}
//add
document.addListener('click',prevent)
//remove
document.removeListener('click',prevent)

preventing effects to be applied to the same object twice when adding objects with ajax

I'm having a little issue with an application I'm making. I have a page where the user edits a document via dragging modules into the page or "canvas" area.
http://thinktankdesign.ca/temp_img.jpg
When the page is loaded, javascript haves the modules collapsible (like above). However after the user drags in a new module the effect is applied again some new modules can collapse as well. here is the problem. each time a module loads the same effect gets applied to the modules that already can collapse. It ends up breaking their animations.
heres the code that gets executed on page load.
//make colapsible
$("h1.handle").click(function() {
var object = $(this);
v$(this).next().toggle("fast", colapsible_class(object));
vreturn false;
}).addClass("open");
and heres the code that gets executed in the creation of a module via ajax
function get_module(id){
var template = $('input[name=template]').val();
$.post(window.location.href, { template: template, module: id, mode: 'create' },
function(data){
$(data).insertBefore(".target_wrapper");
//enable deletion of module
$(".js_no_modules").slideUp("slow");
$(enable_module_deletion());
//show delete button
$("button[name=delete]").show();
//make colapsible
$("h1.handle").click(function() {
var object = $(this);
$(this).next().toggle("fast", colapsible_class(object));
return false;
}).addClass("open");
}
);
}
I need a solid way of preventing the toggle effect to be applied to the same module twice

Use jQuery 1.3 live events instead.
//make colapsible
$("h1.handle").live("click", function() {
var object = $(this);
v$(this).next().toggle("fast", colapsible_class(object));
vreturn false;
}).addClass("open");
and then eliminate the click declaration in the second block of code, changing it to $("h1.handle").addClass("open");
Live events bind all current and future matching elements with an event.

In your Ajax success handler try the following:
//make collapsible
$("h1.handle:not(.open)").click(function() {
var object = $(this);
$(this).next().toggle("fast", colapsible_class(object));
return false;
}).addClass("open");

The best way to solve your problem is, instead of using $("h1.handle") on the AJAX callback, go for $(data).find("h1.handle"). Something like,
var x = $(data);
x.insertBefore(...);
/* your other code */
x.find('h1.handle').click(...).addClass(...);
Like that, only the newly added items will have the event bounded. The already present ones will not be touched.
If we want to answer your question instead of just solving your problem, then we have several alternatives, such as:
store, in your objects, that the onclick event handler has been set so that you don't set it twice
always bind the onclick event, but always unbind it first
use jQuery's live events and the addClass open only on the newly created items.
IMO, the first one is the easiest. You can accomplish it by using jQuery's data(). Then you could do something like:
$("h1.handle").each(function() {
var me = $(this);
// if already has click handler, don't do anything
if (me.data('click_set') != null) { return true; }
// otherwise, store the data and bind the click event
me.data('click_set', true).click(function() {
/* the code you already have on the click handler */
}).addClass('open');
}
The second alternative involves storing the function that you pass inline to the click event binder in a variable, and then using jQuery's unbind to disable it.