CODEWITHSUNDEEP
javascriptjquery
user656925
user656925

Reputation:

What does $ do when using JQuery?

I am reading JavaScript and JQuery, The Missing Manual

and they start of with this Snippet : 

$(document).ready(function(){});

I know that function(){} is an anonymous function, and that document is an object with properties I can set / read, and that ready() is a JQuery function defined in the library, but I don't know what the rest of the syntax is for and it is not explained in the book.

Particularly,

$(document)

Can someone explain what this does or point me to a link? Also, someone said that you can identify JQuery by this alone, is this true?

Upvotes: 7

Views: 3940

Answers (7)

jbabey
jbabey

Reputation: 46657

$ is an alias (short-hand) for the variable jQuery which is the blanket object that stores all jQuery functions.

$(document) is taking your current window.document (the window. part is often omitted when accessing window properties) and passing it to the jQuery constructor $(), and then attaching an event handler to the ready event, which executes the anonymous function passed as a callback.

Upvotes: 1

T. Junghans
T. Junghans

Reputation: 11683

The $ is a synonym for jQuery and what that does is described here: http://api.jquery.com/jQuery/

Upvotes: 1

user1289347
user1289347

Reputation: 2407

the $ before jquery statements is to differentiate between standard javascript and jquery. But other frameworks can use the dollar sign as well, so sometimes you will see jQuery(document) so as not to conflict. It can also be set to anything really, even $jq, etc. All it is doing is telling your code to use the framework functions instead of standard javascript.

Upvotes: 1

charlietfl
charlietfl

Reputation: 171698

$ is a shortcut for the JQuery object. All methods in the jQuery library are part of the jQuery object.

$(selector) is the same as writing 'jQuery(selector)`

Upvotes: 1

Eric Strom
Eric Strom

Reputation: 725

$ is just a selector for jquery. You're pretty much saying that what follows after "$" is part of the jquery library.

Be careful because some other javascript libraries use that same selector.

Upvotes: -3

T.J. Crowder
T.J. Crowder

Reputation: 1075925

$(document) wraps a jQuery instance around the document object. ($ is just an alias for jQuery.) So the return value of $(document) is a jQuery instance, which has a ready function on it.

Upvotes: 4

Sky Kelsey
Sky Kelsey

Reputation: 19290

It is a synonym for the jquery() function:

http://api.jquery.com/jQuery/

Upvotes: 2

Related Questions