JavaScript Strings

JavaScript strings are used to store and manipulate text.

JavaScript Strings

Strings can store a series of characters, like "John Doe".

Strings can be any character inserted into quotes. You can use single or double quotes:

Example

var carname = "Volvo XC60";
var carname = 'Volvo XC60';

You can access each character in a string using its index position:

Example

var character = carname[7];

The index of a string starts from 0, which means the first character has an index value of [0], the second is [1], and so on.

You can use quotes within a string, as long as they do not match the quotes surrounding the string:

Example

var answer = "It's alright";
var answer = "He is called 'Johnny'";
var answer = 'He is called "Johnny"';

You can also use escape characters to include quotes in a string:

Example

var x = 'It\'s alright';
var y = "He is called \"Johnny\"";

String Length

You can calculate the length of a string using the built-in length property:

Example

var txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; var sln = txt.length;

Special Characters

In JavaScript, strings are written within single or double quotes.

Because of this, the following example cannot be parsed by JavaScript:

The string "We are the so-called " is truncated.

To solve this issue, you can use a backslash () to escape the double quotes within the "Vikings" string, like this:

The backslash is an escape character. It converts special characters into string characters:

The escape character () can be used to escape apostrophes, newlines, quotes, and other special characters.

The following table lists special characters that can be escaped within a string:

Strings Can Be Objects

Typically, JavaScript strings are primitive values, created with characters: var firstName = "John"

However, you can also define a string as an object using the new keyword: var firstName = new String("John")

Example

var x = "John";
var y = new String("John");
typeof x; // Returns String
typeof y; // Returns Object

| | Do not create String objects. They slow down execution speed and may produce other side effects: | | --- | --- |

Example

var x = "John";             
var y = new String("John");
(x === y); // Returns false because x is a string and y is an object

=== denotes absolute equality, meaning both the data type and value must be the same.

String Properties and Methods

Primitive values, such as "John", do not have properties or methods (because they are not objects).

However, primitive values can use JavaScript properties and methods, as JavaScript can treat primitive values as objects when executing methods and properties.

String methods will be introduced in the next chapter.

String Properties

String Methods

For more method examples, see: JavaScript String Object.