Difference between " and '

Question

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When to Use Double or Single Quotes in JavaScript
single quotes versus double quotes in js

I'm trying to build a Node.js Express web application, and in the tutorial they use ' instead of " quite often, but there is no explanation why.

Can someone please explain the difference? Is this specific to JavaScript, or does it apply to other languages too?

Example:

app.configure('dev')

app.get("/", function (req, res)

Thanks :)

My opinion: single quotes should always be used when creating a string literal in javascript (caveat: JSON). this is because it makes injected javascript from server side languages much less painful, because they usually use double quotes for their strings. — jbabey, Dec 06 '12 at 18:23

score 8 · Accepted Answer · edited Dec 06 '12 at 18:07

8

In JavaScript, both are equivalent. The only difference is that inside a single-quoted string you don't have to escape ", and vice versa:

'dev' === "dev"
'd"v' === "d\"v"
'd\'v' === "d'v"

Most other languages distinguish the two in some way. For example, in Bash and Perl, '' prevents variables from being expanded inside, so 'a$b' is the actual string a$b, whereas "a$b" is the string consisting of a plus the value of the variable b. In C, C++, C#, and Java, '' is used to create a single character constant, so that 'a' means the character a whereas "a" means a string containing that character.

edited Dec 06 '12 at 18:07

Jonathan Leffler

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answered Dec 06 '12 at 17:58

ruakh

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Thanks alot that made it crystal clear :) – Try to be a success Dec 06 '12 at 18:02
so it would be no problem for me to write app.configure("dev") ? express would not punch me in the face for that? – Try to be a success Dec 06 '12 at 18:04

score 2 · Answer 2 · answered Dec 06 '12 at 17:58

2

Javascript string literals can be enclosed with ' or "; there is no difference between them (except for nesting).
This is not true in most other languages.

answered Dec 06 '12 at 17:58

SLaks

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To expand just a little bit: There is no "common" meaning that JavaScript is violating here. Different languages do totally different things. Ruby and its predecessor interpolate double quoted strings and takes single quoted strings as literals; C uses double quotes for strings and single quotes for characters; Lisp uses double quotes for strings and single quotes for marking data not to be interpreted. – Chuck Dec 06 '12 at 18:02

Difference between " and '

2 Answers2