Is it possible to bind a handler to a jQuery effect? - javascript

I would like to call function when slideUp or slideDown are performed on an element. Is this possible?
Something like:
$('#panel').on('slideUp', function() { open--; });
$('#panel').on('slideDown', function() { open++; });
Update: The problem is that there are a ton of slide calls (e.g.: $().slideUp()) all over the page, within ajax responses, hash link clicks, etc.. I was hoping to bind to the slide itself somehow rather than add code to each calling function.

You cannot bind to an event since there is no such.
But you can pass a handler that will be called after animation is finished
$('#panel').slideUp(function() { ... });
http://api.jquery.com/slideUp/

If you really want to do this, you can use custom events and your own little plugin, something like this:
$.fn.mySlideToggle = function() {
this.slideToggle();
this.trigger('mySlideToggle');
}
$('div').on('mySlideToggle', function(){ console.log('hey') });
$('button').on('click', function(){ $('div').mySlideToggle(); });
Here's a little demo (check console): http://jsbin.com/asejif/2/edit
In your case it is redundant though, since you can use the callback that the slide events provide, but it might be useful for other things...

Related

Infinite Scroll, callback jquery function

I'm using infinite-scroll, a plugin that replaces the standard pagination by fetching new pages through ajax.
The problem with this is that jquery functions don't register the new posts, causing functions like these:
jQuery(document).ready(function($) {
$('.vote-a, .vote-b').click(function() {
//do stuff
});
$('.vote-b').click(function() {
//do other stuff
});
});
to stop running. To solve this, the plugin provides callback, and let's you include codes that you'd like to be called whenever a new page is loaded.
What I did was simply putting the code above there. It worked but I ended up with several instances of the same code.
So the question is how do I solve this? One way I can think of is destroying/removing the old instance with each callback.
Or somehow reinitiliaze/restart/invoke the function.
You can register the click events at a root level instead of by finding the individual elements and assigning a click event to them.
https://api.jquery.com/on/
and the older method
https://api.jquery.com/live/
jQuery(document).ready(function($) {
$(document).on('click', '.vote-a, .vote-b', function() {
//do stuff
});
$(document).on('click', '.vote-b', function() {
//do other stuff
});
});

Elegant way to write repeated function

In JS / jQuery there's often a need to do something and then repeat it under certain circumstances.
For example something like this, it's only an example:
$(window).load(function() {
scaleSomething();
$(window).resize(function() {
scaleSomething();
});
});
What would be the elegant way to write something like this? Because in such situations one function / block of code is always doubled.
You have to use .on to bind multiple events. Please read here to know more about it.
Try,
$(window).on('load resize',scaleSomething)
You can group space-separated events when using ".on" method:
$(window).on("load resize", function() {
scaleSomething();
});
http://api.jquery.com/on/
Try to trigger the event immediately after you create a listener:
$(window).on('resize', function() {
scaleSomething()
}).trigger('resize');
Use on to attach an event handler to multiple events. The events are passed as the first argument to the on function. The argument should be a string with event names delimited by spaces.
$(window).on("load resize", function(){
scaleSomething();
});
function scaleSomething(){
alert("scaling");
}
JS Fiddle: http://jsfiddle.net/7ZFpr/

Jquery: bind load + change simultaneously

In many cases, I need to bind a behaviour to an element after loading, and then after an event triggering (like "change").
I think the best way would be to make it in the same line:
$('#element_id').bind('load, change', function () {
...
});
But this works only for "change" and not for "load". There is a better way?
I stumbled across the same problem. Removing comma is not enough, at least not in this case:
$(document).ready(function(){
$('#element_id').bind('load change', function () {
... // (this DOESN'T get called on page load)
});
});
I guess load events get triggered before $(document).ready().
This is a simple solution:
$(document).ready(function(){
$('#element_id').bind('change', function () {
...
});
$('#element_id').trigger('change');
});
For already loaded content, when you want to run a function on an event and also straight away, you can use a custom event of your own naming to avoid triggering any existing bindings from libraries etc. on the built in events, e.g.
$(".my-selector").on("change rightnow", function() {
// do stuff...
}).triggerHandler("rightnow");
Don't you just need to remove the comma?
try it without the comma:
$('#element_id').bind('load change', function () {
...
});
http://api.jquery.com/bind/#multiple-events

Jquery bind()/live() within a function

I wrote a little pager which removes and rewrites content. I have a function called after loading the page, it shall be executed after changing the page as well. Because I do not wat to implement the function twice (on initialisation and after changing the page) I tried bind()/live() and a simple function.
The function looks like this:
jQuery('.blogentry').each(function (){
jQuery(this).click(function(){
//Clicking on the element opens a layer, definitely works - I tested it
});
});
It is executed after initialisation, for executing it after page changes as well I tried the following:
jQuery('.nextPage, .prevPage').click(function changePage(){
// Changing page and rewriting content
showEntry();
});
//...
showEntry();
//...
function showEntry(){
jQuery('.blogentry').each(function (){
jQuery(this).click(function(){
//Clicking on the element opens a layer, definitely works - I tested it
});
});
}
But the function is not executed if put inside a function (lol) and called via showEntry();
Afterwards I tried to bind the function...
jQuery('.nextPage, .prevPage').click(function changePage(){
// Changing page and rewriting content
jQuery('.blogentry').bind("click", showEntry);
});
//...
jQuery(this).click(function showEntry(){
//Clicking on the element opens a layer, definitely works - I tested it
});
Did not work either. Code after the bind()-line would not execute as well.
I thought maybe it's a problem to bind to an event function, if an event is already given via the parameter so i also tried this:
jQuery('.nextPage, .prevPage').click(function changePage(){
// Changing page and rewriting content
jQuery('.blogentry').bind("click", showEntry);
});
//...
function showEntry(){
//Clicking on the element opens a layer, definitely works - I tested it
});
}
No success at all. Maybe I cannot call the function from inside the function regarding to the bind()? Maybe I just do not understand the bind()-function at all? I also tried the live() function since it seemed to fit better, as I am rewriting the content all the time. But it had the same effect: none...
The simplest way to implement this should be
jQuery('.blogentry').live('click', function() { /* onclick handler */ });
This should bind the function to every blogentry on the page at the moment of the call and all the blogentries that are added to the page later on.
Additional notes:
In $(foo).each(function() { $(this).click(fun); }); the each is unnecessary - $(foo).click(fun); is enough.
$(foo).bind('click', fun); is functionally equivalent to $(foo).click(fun) - it does not matter which one you use.
You can use delegate or bind. don't call the function like that, just create a delegate with .blogentry and it should update even after you load a new page via ajax. It will automatically do this.
$("#blogcontainer").delegate(".blogentry", "click", function(){ //open layer });
This should work for you
$(body).delegate(".blogentry", "click", function(){
showEntry();
});
alternaltivly you can use event delegation
$(document).ready(function () {
$('#blogcontainer').click( function(e) {
if ( $(e.target).is('.blogentry') ) {
// do your stuff
}
});
});
hence, no need to bind each blogentry at creation or reload, and it's (slightly) faster.

Add click event to Div and go to first link found

I think I've been too much time looking at this function and just got stuck trying to figure out the nice clean way to do it.
It's a jQuery function that adds a click event to any div that has a click CSS class. When that div.click is clicked it redirects the user to the first link found in it.
function clickabledivs() {
$('.click').each(
function (intIndex) {
$(this).bind("click", function(){
window.location = $( "#"+$(this).attr('id')+" a:first-child" ).attr('href');
});
}
);
}
The code simply works although I'm pretty sure there is a fairly better way to accomplish it, specially the selector I am using: $( "#"+$(this).attr('id')+" a:first-child" ). Everything looks long and slow. Any ideas?
Please let me know if you need more details.
PS: I've found some really nice jQuery benchmarking reference from Project2k.de here:
http://blog.projekt2k.de/2010/01/benchmarking-jquery-1-4/
Depending on how many of these div.click elements you have, you may want to use event delegation to handle these clicks. This means using a single event handler for all divs that have the click class. Then, inside that event handler, your callback acts based on which div.click the event originated from. Like this:
$('#div-click-parent').click(function (event)
{
var $target = $(event.target); // the element that fired the original click event
if ($target.is('div.click'))
{
window.location.href = $target.find('a').attr('href');
}
});
Fewer event handlers means better scaling - more div.click elements won't slow down your event handling.
optimized delegation with jQuery 1.7+
$('#div-click-parent').on('click', 'div.click', function () {
window.location.href = $(this).find('a').attr('href');
});
Instead of binding all the clicks on load, why not bind them on click? Should be much more optimal.
$(document).ready(function() {
$('.click').click(function() {
window.location = $(this).children('a:first').attr('href');
return false;
});
});
I would probably do something like;
$('.click').click(function(e){
window.location.href = $(this).find('a').attr('href');
});

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