What is the meaning of symbol $ in jQuery?

Solution 1:

The jQuery object :)

From the jQuery documentation:

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

So, using $("#id") or jQuery("#id") is the same.

Solution 2:

Strange but true, you can use "$" as a function name in JavaScript. It is shorthand for jQuery(). Which you can use if you want. jQuery can be ran in compatibility mode if another library is using the $ already. Just use jQuery.noConflict(). $ is pretty commonly used as a selector function in JS.

In jQuery the $ function does much more than select things though.

You can pass it a selector to get a collection of matching elements from the DOM.
You can pass it a function to run when the document is ready (similar to body.onload() but better).
You can pass it a string of HTML to turn into a DOM element which you can then inject into the document.
You can pass it a DOM element or elements that you want to wrap with the jQuery object.

Here is the documentation: https://api.jquery.com/jQuery/

Solution 3:

It is syntactic sugar. It is not specific only to jQuery; other libraries use it as well. You can look for a full-details article about the use of dollar sign in JavaScript here.

Solution 4:

As said in other answers $ is a shortcut to the jQuery function.

Some JavaScript libraries uses $ too (example: prototype). To avoid conflict with those other libraries jQuery provides jQuery.noConflict() function. Calling this function the control of the $ variable goes back to the other library that first implemented it. Doing this to use jQuery you can't do this $('div.someClass') anymore, instead jQuery('div.someClass').

Alternatively can do this:

jQuery.noConflict();

jQuery.ready(function($) {
   // use $ for jQuery
}

//use $ for the other library

When writing plugins to avoid problems with the usage of noConflict you can pass 'jQuery' to a function:

function($) {

//use $ writing your plugin

}(jQuery)

Solution 5:

$ is simply a function called jQuery. It is how you access all of the functionality in the jQuery lib.

You can find it here: http://docs.jquery.com/%24