$ at the beginning and at the end of variable

Question

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Why would a JavaScript variable start with a dollar sign?

I realized some syntax with jquery and didnt know what it is. here goes:

var $foo = $("bar").blah();

var hello$ = $("stgelse").etc();

What is the difference between these? and why are they like that?

Also, For example:

var $foo = $("").blah();

var should already contain whatever right side is returning ? no?

Can you please elaborate?

It's just a convention so you can tell at a glance that the variable is a jQuery object. There's nothing special about that syntax since `$` is a valid character. — elclanrs, Dec 04 '12 at 07:31
so there is no magic? cool why dont u put that as answer. thanks. — DarthVader, Dec 04 '12 at 07:32
this link can be useful : http://stackoverflow.com/questions/1916584/jquery-variable-syntax — Sirwan Afifi, Dec 04 '12 at 07:35
`$` can be used in the middle as well, e.g. `var holy$hit = intensify($hit);` — Salman A, Dec 04 '12 at 08:26
I have also seen it used to indicate observables e.g. `abc$: Observable;` — Amin, Mar 17 '22 at 23:28

score 7 · Answer 1 · answered Dec 04 '12 at 07:41

In Javascript you can use $ in a variable name (or as a variable name all by itself, like it's used by the jQuery library for example), there is no special meaning in the language itself.

Some people use $ at the beginning of a variable name to indicate that the variable should contain a jQuery object, for example:

var $form = $('form');

A $ at the end of variable names was used in BASIC for string variables, which might be one reason for using it to mean something when naming variables in other languages also. Example:

10 LET NAME$="JOHN DOE"
20 PRINT NAME$

score 4 · Accepted Answer · edited May 23 '17 at 10:29

4

var $foo = $("bar").blah();

var is a keyword that makes the variable local in certain cases. See this question
$foo is the name of this variable. There is no need for the $, and indeed it confuses everything, but some languages (like PHP) need them to say "this is a variable". It could've been just foo
= is the assignment to make $foo have whatever comes from the right hand side
$ is another variable, but a special one: this is your JQuery thingy! From there you see it does all the JQuery stuff, like "find bar, do blah() etc.

The same basically goes for the other line, but in this case someone thought that hello$ would be a nice name for a var :)

edited May 23 '17 at 10:29

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answered Dec 04 '12 at 07:34

Nanne

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+1 ---but 3 point loled me .... op is 6k rep user – NullPoiиteя Dec 04 '12 at 07:41
But now it's an ultra=cannonical answer :) – Nanne Dec 04 '12 at 07:44
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@NullPointer rep doesnt mean anything (sometimes). i wrok at Y! but never used javascript really. just copy paste so i was reading some stuff about it. js is cryptic:) – DarthVader Dec 04 '12 at 07:47
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@DarthVader if are new try http://www.codecademy.com/tracks/javascript-combined i loveed that – NullPoiиteя Dec 04 '12 at 07:50

score 2 · Answer 3 · edited May 23 '17 at 12:18

2

here

var hello$ and $foo

hello$ , $foo are just a variable name

and $("").blah();

$ is jquery object

edited May 23 '17 at 12:18

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answered Dec 04 '12 at 07:33

NullPoiиteя

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score 1 · Answer 4 · answered Dec 04 '12 at 07:34

$ is just a name - names in JavaScript can contain dollar signs, and can consist of just a dollar sign.

Its like just normal javascript variable but as per convention is used to identify jquery objects variable from normal javascript variable. there nothing special about it.

$ at the beginning and at the end of variable

4 Answers4