What is the meaning of symbol $ in jQuery?
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.
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)
The jQuery object :)
From the jQuery documentation:
By default, jQuery uses "$" as a shortcut for "jQuery"
So, using $("#id") or jQuery("#id") is the same.
Strange but true, you can use "$" 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/