JavaScript Strings


What is a String?

In JavaScript, a string is a sequence of characters used to represent text. Strings are enclosed either in:

  • Single quotes ' '
  • Double quotes " "
  • Backticks ` ` (Template Literals)

How to Create a String?

You can create a string in two ways:



1. Using String Literals

let name = "John";
let city = 'New York';


2. Using the String Object

let greeting = new String("Hello World");
          

Tip: Prefer string literals because they are simpler and faster.


Examples and Outputs



Example 1: Single and Double Quotes

let str1 = 'Hello';
let str2 = "World";

console.log(str1);  // Output: Hello
console.log(str2);  // Output: World


Example 2: Using Quotes Inside Strings

You can use opposite quotes inside:

let str3 = "It's a beautiful day";
let str4 = 'He said, "Hello!"';

console.log(str3);  // Output: It's a beautiful day
console.log(str4);  // Output: He said, "Hello!"

If needed, you can also use escape characters:

let str5 = 'It\'s a beautiful day';
let str6 = "He said, \"Hello!\"";

console.log(str5);  // Output: It's a beautiful day
console.log(str6);  // Output: He said, "Hello!"


String Properties

  • length — Returns the length of the string.
let str = "JavaScript";

console.log(str.length); // Output: 10


Common String Methods

Method Description Example Output
toUpperCase() Converts to uppercase "hello".toUpperCase() HELLO
toLowerCase() Converts to lowercase "HELLO".toLowerCase() hello
includes() Checks if substring exists "JavaScript".includes("Script") true
indexOf() Finds position of substring "JavaScript".indexOf("Script") 4
slice(start, end) Extracts part of string "JavaScript".slice(0, 4) Java
replace(old, new) Replaces part of string "Hello World".replace("World", "JS") Hello JS
trim() Removes spaces " Hello ".trim() Hello


Template Literals (Backticks)

Template literals allow:

  • Multi-line strings
  • String interpolation (inserting variables)
let name = "Alice";
let greeting = `Hello, ${name}!`;

console.log(greeting); // Output: Hello, Alice!

Multi-line example:

let message = `This is
a multi-line
string.`;

console.log(message);
// Output:
// This is
// a multi-line
// string.


Escape Characters

Sometimes you need special characters inside strings:

Escape Sequence Meaning Example Output
\' Single quote 'It\'s sunny' It's sunny
\" Double quote "He said \"Hi\"" He said "Hi"
\\ Backslash "C:\\path\\to\\file" C:\path\to\file
\n New line "Hello\nWorld" Hello
World
\t Tab space "Hello\tWorld" Hello World


Quick Recap

  • A string holds text.
  • Use " ", ' ', or ` ` to define strings.
  • .length, .toUpperCase(), .slice() are common methods.
  • Template literals (`) make dynamic text easy.