Declaring variables javascript

Question

I just have a quick question and cant find anything on google. I was going through some code another programmer put together and he declares ALL of his javascript variables with $ in front of them...for instance:

 var $secondary;

Is there a reason for this? Could this cause problems in the future if JQuery ever ends up being used. I'm just curious because I was going to clean it up if so.

Have a look at this: http://stackoverflow.com/a/553734/1650716 — nix, May 20 '13 at 03:37
Take a look at this: http://stackoverflow.com/questions/205853/why-would-a-javascript-variable-start-with-a-dollar-sign — Jonast92, May 20 '13 at 03:37
That must be painful to see every variable prefixed with a $. — Anurag, May 20 '13 at 03:37

score 3 · Answer 1 · answered May 20 '13 at 03:38

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Is there a reason for this?

Hard to say. Maybe he came from a PHP background where $ prefixes the variables. Maybe he's a jQuery addict. Who knows? You'd have to ask him. That aside, $ is a perfectly legitimate character to use in a JavaScript variable name but as you noted, it could cause issues with jQuery. But that's why jQuery offers a noConflict() option.

answered May 20 '13 at 03:38

j08691

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how you can get a confilct if you dont use asing `$` to a function or value? – Juan Antonio Orozco May 20 '13 at 03:39
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Why would it cause a conflict? That's like saying `apple` will conflict with a variable named `a`. – icktoofay May 20 '13 at 03:39
Ok, I re-worded that part of my answer. – j08691 May 20 '13 at 03:40
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I still see "it could cause issues with jQuery" in your answer. – icktoofay May 20 '13 at 03:41
@icktoofay - by issues I mean if the OP ever decides to add jQuery to this project, it may cause undue confusion when debugging or troubleshooting. Merely having a variable with `$` wouldn't be a specific problem. – j08691 May 20 '13 at 03:42
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Oh, I see. I'd still reword it to be clearer that it wouldn't cause technical difficulties but rather cause confusion. – icktoofay May 20 '13 at 03:44

score 1 · Answer 2 · answered May 20 '13 at 03:38

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$ is a valid variable character, and in PHP all variables start with it. It's possibe that that particular developer uses $ as a "flag" to mean "this is a variable". It has no special meaning.

answered May 20 '13 at 03:38

Niet the Dark Absol

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score 1 · Answer 3 · answered May 20 '13 at 03:38

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$ just a character that you can use in a variable name. Some people like to use it to denote variables that contain jQuery objects:

var $foo = $('#foo');
var bar = 42;

But that's just a personal preference. It has no special meaning.

answered May 20 '13 at 03:38

Blender

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score 1 · Accepted Answer · answered May 20 '13 at 03:38

I use this convention too keep track of if a variable is storing a JQuery object. So say the function getJQueryObject() returns a JQuery object and I want to store it.

i.e:

var $myJQobj = getJQueryObject();

Makes it clear that $myJQobj is a JQuery object unlike i.e

var myStr = "hello";

The $ as the first character in the identifier doesn't have any special meaning, you aren't invoking a method like $(), it's just a perfectly valid identifier in JavaScript. But the factthat the $ is used in JQuery makes what I was talking about before even clearer.

random-forest-cat · Answer 5 · 2014-03-14T03:30:24.120

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its just a convention for jQuery DOM selctions.

var $logo = $('a.logo');

it wont cause any issues - it just lets other devs know that you're working with a jQuery wrapped dom element.

edited Mar 14 '14 at 03:30

answered May 20 '13 at 03:49

random-forest-cat

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score 0 · Answer 6 · answered May 20 '13 at 03:38

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$ is fine for use in JavaScript. PHP uses the same variable syntax so maybe he was used to it from that.

answered May 20 '13 at 03:38

Phillip Berger

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Declaring variables javascript

6 Answers6