Develop Reference

jQuery alias for script specific

Wordpress ships jQuery in safe mode, this is very awesome, but a 3rd party script that I must use uses the $ alias, so there's a way of alias $ to jQuery only for that script ? (can't edit the script since it's 3rd party)

wrap the initialisation of the plugin in an IIFE
(function($){
$('.some').pluginUsingDollarAsJQuery();
})(jQuery)
As per the help pages for plugin authorship:
The $ variable is very popular among JavaScript libraries, and if you're using another library with jQuery, you will have to make jQuery not use the $ with jQuery.noConflict(). However, this will break our plugin since it is written with the assumption that $ is an alias to the jQuery function. To work well with other plugins, and still use the jQuery $ alias, we need to put all of our code inside of an Immediately Invoked Function Expression, and then pass the function jQuery, and name the parameter
Which basically boils down to the fact that whoever has written the plugin you're using has not done it right.
Writing a plugin like this:
$.fn.doSomething = function(){
// whatever
}
Will make it not compatible with anyone using jQuery in noConflict mode. It should be wrapped in an IIFE like this:
(function($){
$.fn.doSomething = function(){
// whatever
}
})(jQuery)
If your plugin is the former style, ditch it.

Jamiec's answer is the clean solution which should be used if you have access to the code, but in case you do not have access to it, there is a dirty solution.
You can reassign $ to jQuery just before the script is loaded. So when the script is initializing, $ === jQuery.
To do it when the script is inline in the DOM, just open a script tag for the reassignment before :
<script>$=jQuery;</script>
<script src="external_script"></script>
If you load dynamically the script (ex : jQuery.getScript), you can reassign just before calling the async function :
window.$ = jQuery;
jQuery.getScript('external_source');
WARNING : this method can break your script if window.$ was used elsewhere. It may also not work if the script is loaded asynchronous if, meanwhile, another script reassign $ to something else.

$ not working for jQuery in new website

I have been using jQuery for quite a few years now, and after I include the jQuery scripts in whatever site I am working on, I would always use the $ for jQuery objects. For example:
$('#my_selector').click(function(){...
I had built a website a few years ago in Joomla 1.6 with over 200 pages and jQuery used in almost all of them, all with the $. Now I am rebuilding the site in Joomla 3.3.0. The funny thing is, now sometimes the $ just doesn't work when identifying jQuery objects, but when I use jQuery it works. For example. the above code example would have to be changed to this:
jQuery('#my_selector').click(function(){...
And that works. And the final strangest thing is that on one page, it seems like the $ works for some of the jQuery but not all. The error that I see is this one:
TypeError: undefined is not a function
Seems like the problem occurs mostly on the functions that run after load complete circumstances. Anyway I am just wondering if people out there know why the $ would stop working with identifying the jQuery functions and objects.
Thanks!

You are most probably using a conflicting library, meaning: another script/library that declares (and thus overrides) the variable $. Wrap all your code in a closure, and you should be good:
(function($) {
$('#my_selector').doStuff();
})(jQuery)
Or, if it needs to be executed after document ready:
jQuery(document).ready(function($) {
$('#my_selector').doStuff();
});

Joomla 3.x is moving progressively to jQuery and replacing all MooTools dependencies along the way.
The default state is to load jQuery in noConflict() mode, but depending on features used on any given page by extensions (templates,plug-ins, components or modules) MooTools may also be loaded.
That means that on some pages, jQuery is defined and not $ and on other pages both are defined, obviously this will result in the issues you are seeing.
Add to that most third-party extensions from the 1.6 era (you have been upgrading to the 2.5.x line along the way right?) just ignored what-ever was going on and loaded whatever they needed (potentially blowing away other libraries) you generally will have to sort out all the conflicts first.
The only guaranteed way to use jQuery is by using the jQuery prefix.
You can read about using JavaScript frameworks with Joomla here, amongst other things it gives you future proof mechanism built-in to Joomla for loading jQuery.
To load jQuery, use: JHtml::_('jquery.framework');
To load the jQuery UI core call: JHtml::_('jquery.ui');
As has been mentioned you can wrap your JavaScript in a closure, in fact this is what the core com_banners does in /media/cbanner.js
var jQuery;
(function ($) {
$(document).ready(function () {
$('#jform_type').on('change', function (a, params) {
var v = typeof(params) !== 'object' ? $('#jform_type').val() : params.selected;
switch (v) {
case '0':
// Image
$('#image, #url').show();
$('#custom').hide();
break;
case '1':
// Custom
$('#image, #url').hide();
$('#custom').show();
break;
}
});
});
})(jQuery);

Are you or joomla using mootools or any other library with the $?
This would mean there is a conflict and the right way to solve it, is by using jQuery instead of $.

jQueryUI and jQuery Plugin Conflict

I am using a jQuery plugin that goes in conflict with something in the jQueryUI Effects Core, much probably something to do with ease animation.
I can't post the code because the plugin is not open source, so my question is: is there any way I can catch this error and fix it?
In the jQueryUI Effects Core, both plugin work properly with no conflicts if I remove the following code
$.effects = {
effect: {}
};
I don't even know what's that for, so I would like to understand.
Thanks in advance to anyone who will try to help me.

I would use the development version of jQuery, if you are looking for a conflict within the library itself. I'm certain you are already using some sort of debug tool, such as firebug, or chromes javascript console. From there you just need to find the error and get a stack trace. Firefox's "Break on all errors" feature is useful in this case.
Also don't be afraid to add your own code to the development version of jquery. Mess it up and treat it as your own code, you can always download it again.
good luck!

Many JavaScript libraries use $ as a function or variable name, just as jQuery does. In jQuery's case, $ is just an alias for jQuery, so all functionality is available without using $. If we need to use another JavaScript library alongside jQuery, we can return control of $ back to the other library with a call to $.noConflict():
<script type="text/javascript" src="other_lib.js"></script>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$.noConflict();
// Code that uses other library's $ can follow here.
</script>
This technique is especially effective in conjunction with the .ready() method's ability to alias the jQuery object, as within callback passed to .ready() we can use $ if we wish without fear of conflicts later:
<script type="text/javascript" src="other_lib.js"></script>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$.noConflict();
jQuery(document).ready(function($) {
// Code that uses jQuery's $ can follow here.
$("div").hide();
});
// Code that uses other library's $ can follow here.
$("content").style.display = 'none';
</script>
Source: jQuery.noConflict

Defining a scope for JQuery variables, different js - single page

I have 2 js on a single page. In one of the js I am doing var jQuery = $.noConflict(true); and after that using all the jQuery methods using jQuery object, like jQuery("#div").hide();
In another js, I am using the traditional $ variable & accessing the jQuery methods as $("#div").hide();
When on a page I use either of the 2 js', things work fine. However, when I include both, the $ in the second js seems to be overwritten by jQuery. for example, in js 2 I can no longer do $("#div").hide() but if I use jQuery instead of $, it works fine - jQuery("#div").hide();!
Why am I experimenting this is because the first div will be distributed to different websites as a plugin, and the second js could be the Jquery written by that website developer.
Please help me figure out where am I going wrong..
Thanks.

You're using noConflict, which releases jQuery's hold on $. Doesn't matter if it's in separate scripts, since it's the same global environment.
In the script where you want to use $, define that variable inside your .ready() handler.
jQuery(function($) {
$('foo').bar();
});

The easiest way to solve this is to use a pattern that plugin authors employ.
(function($) {
// Use $ safely within the function
})(jQuery); // Passes in jQuery object
This is function is created and invoked immediately, and at the same time allows you to pass a variable into the scope of the function. Using this, you can carry on referring to $ in your code and not worry about overwriting it or conflicting.
The jQuery documentation advises this pattern

Files do not have scope, you dereferenced $ with noConflict for your entire page. Anything

Using jQuery and Mootools

So I need to provide a library for my client that displays a map, but I want to write this library using Mootools but the client has jQuery on his website. So my question is how will this affect the client website and what is the best way to avoid any conflicts.

Use this function
jQuery.noConflict();
but keep in mind that you will no longer be able to use the dollar sign for jQuery. Instead you'll always have to write jQuery("selector")... etc.
see also: http://api.jquery.com/jQuery.noConflict/
jQuery.noConflict();
(function($) {
$(function() {
// more code using $ as alias to jQuery
});
})(jQuery);
// other code using $ as an alias to the other library

You can declare this code:
jQuery.noConflict();