JavaScript Strings

In JavaScript, a string is a sequence of characters enclosed in single or double quotation marks. Strings are used to represent text and are one of the fundamental data types in the language.

Here are some examples of strings:

var greeting = "Hello, world!";

var message = 'Welcome to JavaScript!';

var name = "John";

In the examples above, the strings "Hello, world!", 'Welcome to JavaScript!', and "John" are assigned to the variables greeting, message, and name, respectively.

Strings in JavaScript have several properties and methods that allow you to manipulate and work with them. Here are some commonly used properties and methods:

1. Length property: The length property returns the number of characters in a string.
   
   

var greeting = "Hello, world!";

console.log(greeting.length); // Output: 13

Accessing characters: You can access individual characters in a string using bracket notation and a zero-based index.

var name = "John";

console.log(name[0]); // Output: "J"

console.log(name[2]); // Output: "h"

Concatenation: You can concatenate strings using the concatenation operator (+) or the concat() method.

var firstName = "John";

var lastName = "Doe";

var fullName = firstName + " " + lastName;

console.log(fullName); // Output: "John Doe"

var message = firstName.concat(" ", lastName);

console.log(message); // Output: "John Doe"

String methods: JavaScript provides various built-in methods to manipulate strings. Some commonly used methods include:

• toUpperCase(): Converts a string to uppercase.
  
  

var name = "John";

console.log(name.toUpperCase()); // Output: "JOHN"

toLowerCase(): Converts a string to lowercase.

var name = "JOHN";

console.log(name.toLowerCase()); // Output: "john"

substring(startIndex, endIndex): Extracts a portion of a string based on the specified start and end indexes.

var message = "Hello, world!";

console.log(message.substring(7, 12)); // Output: "world"

indexOf(searchValue): Returns the index of the first occurrence of a specified value within a string.

var message = "Hello, world!";

console.log(message.indexOf("world")); // Output: 7

split(separator): Splits a string into an array of substrings based on a specified separator.

var names = "John, Jane, Mike";

console.log(names.split(", ")); // Output: ["John", "Jane", "Mike"]

1. • 
     

2. These are just a few examples of the many available string methods in JavaScript. You can refer to the JavaScript documentation for a complete list of string methods.

Strings are versatile and widely used in JavaScript for tasks such as displaying text, manipulating input, and handling textual data in various applications.