jQuery的$是多少。 参考？ [关闭]

                <div class="grid--cell fl1 lh-lg">
                    <div class="grid--cell fl1 lh-lg">
                        This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time,   or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making   this question more broadly applicable, <a href="/help/reopen-questions">visit the help center</a>.

                    </div>
                </div>
            </div>
            <div class="grid--cell mb0 mt8">Closed <span title="2012-12-04 15:27:51Z" class="relativetime">7 years ago</span>.</div>
        </div>
    </aside>

I've seen $. used but I've never understood what it stands for. Example that got me thinking:

$.getJSON("url", function(result){
                    $.each(result, function(i, field){
                        $(".test").append(field + " ");
                    });

EDIT: Right, I'm embarrassed. I knew it referred to jQuery but I've only used jQuery for DOM manipulation, I'm so used to having elements to be worked on, it threw off guard a little. Thanks for your informative replies.

</div>

It's an alias for the jQuery object itself, so instead of having to write:

jQuery.getJSON("url", function(result){
                    jQuery.each(result, function(i, field){
                        jQuery(".test").append(field + " ");
                    });

you can write the more convenient code (as you have posted)

$ is an alias for jQuery - see the very top of the library for the code.

According to the JQuery documentation:

By default, jQuery uses "$" as a shortcut for "jQuery"

It's same as your full name is 'Meghananth Rahtod' and people call you Megh.

The easy case - $ and jQuery are the same thing assigned to different variables.

$ is the main jQuery object, which is actually a function that you can call, hence the ability to do

$(selector)

However, functions in JavaScript are objects themselves, so you can attach methods to them and call them later. So $.each is actually a method on the $ object.

Basically $. is not something special about jQuery, but simple method invocation.

Just an alias to the jQuery object. Both $ and jQuery do the same.

This is a part of jQuery source code:

// Expose jQuery to the global object
window.jQuery = window.$ = jQuery;

You can access to this here: http://code.jquery.com/jquery-1.8.3.js
jQuery is open-source.

It might be confusing, but $ is a valid identifier in Javascript.

It's an alias for jQuery. The $ is a function of jQuery, but when you use $(""), $(null), $(undefined) or $(false), the jQuery return "this", making the call to itself. In the line 100 of jQuery file (development, version 1.8.3) you can see this.

Other ways to call the jQuery: window.jQuery, window.$ or jQuery.

You can see more here too: http://www.hackification.com/2008/11/27/a-developers-introduction-to-jquery/