When Should I Use Double or Single Quotes in JavaScript

When should I use double or single quotes in JavaScript?

The most likely reason for use of single vs. double in different libraries is programmer preference and/or API consistency. Other than being consistent, use whichever best suits the string.

Using the other type of quote as a literal:

alert('Say "Hello"');
alert("Say 'Hello'");

This can get complicated:

alert("It's \"game\" time.");
alert('It\'s "game" time.');

Another option, new in ECMAScript 6, is template literals which use the backtick character:

alert(`Use "double" and 'single' quotes in the same string`);
alert(`Escape the \` back-tick character and the \${ dollar-brace sequence in a string`);

Template literals offer a clean syntax for: variable interpolation, multi-line strings, and more.

Note that JSON is formally specified to use double quotes, which may be worth considering depending on system requirements.

What is the difference between single or double quotes in my JS and CSS?

The most important thing is to be consistent. Use the same quote style throughout the same project. If you enjoy writing JavaScript with single-quotes, please do. But If your teammate likes to use double-quotes, agree on what style to use before working.

Additional information:

• When to use double or single quotes in JavaScript?
• Which type of quotes we should use in css background url ("....")? Single, double or no quote needed?

Double quotes vs single quotes in JavaScript

The difference is that you don't need to escape single quotes in double quotes, or double quotes in single quotes. That is the only difference, if you do not count the fact that you must hold the Shift key to type ".

When should I use double or single quotes in JavaScript?

The most likely reason for use of single vs. double in different libraries is programmer preference and/or API consistency. Other than being consistent, use whichever best suits the string.

Using the other type of quote as a literal:

alert('Say "Hello"');
alert("Say 'Hello'");

This can get complicated:

alert("It's \"game\" time.");
alert('It\'s "game" time.');

Another option, new in ECMAScript 6, is template literals which use the backtick character:

alert(`Use "double" and 'single' quotes in the same string`);
alert(`Escape the \` back-tick character and the \${ dollar-brace sequence in a string`);

Template literals offer a clean syntax for: variable interpolation, multi-line strings, and more.

Note that JSON is formally specified to use double quotes, which may be worth considering depending on system requirements.

Difference between single quotes and double quotes in Javascript

You'll want to use single quotes where you want double quotes to appear inside the string (e.g. for html attributes) without having to escape them, or vice versa. Other than that, there is no difference.

However, note that JSON (JavaScript Object Notation) only supports double quoted strings.

Does the type of quotes matter when using use strict?

Actually in Javascript using double quotes or single quotes doesn't change anything.

It's more important you use the same option in your entire code.

Even if you use mixed quotes it will not change anything:

'use strict'
var myString = "double quotes string"

So using use strict with double quotes or single quotes are the same.

In many libraries they commonly use one of them for strings and another to avoid escape, like in this example:

'A string that\'s single quoted'

"a string that's double quoted"

So specifically in English sometimes is useful using double quotes instead of single quotes to avoid this kind of escape thing.

Single vs Double quotes (' vs )

The w3 org said:

By default, SGML requires that all attribute values be delimited using either double quotation marks (ASCII decimal 34) or single quotation marks (ASCII decimal 39). Single quote marks can be included within the attribute value when the value is delimited by double quote marks, and vice versa. Authors may also use numeric character references to represent double quotes (") and single quotes ('). For double quotes authors can also use the character entity reference ".

So... seems to be no difference. Only depends on your style.

When to use double quotes/single quotes in parentheses?

Variable value should be in quotes , variable name should not be in quotes .

convertToInteger("56");

or

var datavalue="56";

convertToInteger(datavalue);

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