Introduction
In JavaScript, identifiers are the names used to identify variables, functions, and objects. They must start with a letter, an underscore (_), or a dollar sign ($) and can be followed by letters, digits, or underscores. Identifiers are case-sensitive and cannot be JavaScript reserved keywords.
In this article, you will learn about JavaScript identifiers, their rules, best practices for naming variables, and examples of valid and invalid identifiers.
Example of Identifier
An identifier is simply the name of a variable, function, or object in JavaScript. Here’s an example of JavaScript identifiers:
// Variable Identifiers
let studentName = "John";
let age = 21;
// Function Identifier
function calculateSum(a, b) {
return a + b;
}
// Object Identifier
let person = {
firstName: "Alice",
lastName: "Brown"
};
console.log(studentName);
console.log(age);
console.log(calculateSum(5, 10));
console.log(person.firstName); 
You can also try this code with Online Javascript Compiler
Output
John
21
15
Alice
Explanation:
- studentName and age are variable identifiers.
- calculateSum is a function identifier.
- person is an object identifier, and firstName & lastName are property identifiers.
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