Question
Answer and Explanation
JavaScript code is primarily composed of statements, which are instructions that tell the browser what to do. These statements can include variable declarations, function definitions, conditional logic, loops, and more. Here's a breakdown of what JavaScript code typically looks like:
1. Variables:
- Variables are used to store data. They are declared using keywords like var, let, or const. For example:
let userName = "Alice";
const PI = 3.14159;
var age = 30;
2. Data Types:
- JavaScript supports various data types, including numbers, strings, booleans, arrays, objects, and more. Examples:
let count = 10; // Number
let message = "Hello, World!"; // String
let isTrue = true; // Boolean
let colors = ["red", "green", "blue"]; // Array
let person = { name: "Bob", age: 25 }; // Object
3. Operators:
- Operators are used to perform operations on variables and values. Common operators include arithmetic (+, -, , /), assignment (=), comparison (==, ===, !=, >, <), and logical (&&, ||, !). Example:
let sum = 5 + 3; // Addition
let isEqual = (10 == "10"); // Comparison (loose equality)
let andResult = (true && false); // Logical AND
4. Conditional Statements:
- Conditional statements (if, else if, else) allow you to execute code based on certain conditions. Example:
if (age >= 18) {
console.log("Adult");
} else {
console.log("Minor");
}
5. Loops:
- Loops (for, while, do...while) are used to repeat a block of code multiple times. Example:
for (let i = 0; i < 5; i++) {
console.log(i);
}
6. Functions:
- Functions are blocks of code that can be called to perform a specific task. They are defined using the function keyword. Example:
function greet(name) {
return "Hello, " + name + "!";
}
let greeting = greet("Charlie");
7. DOM Manipulation:
- JavaScript can interact with the HTML document using the Document Object Model (DOM). This allows you to modify the content, structure, and style of a web page. Example:
document.getElementById("myElement").innerHTML = "New Content";
8. Event Handling:
- JavaScript can respond to user interactions (events) such as clicks, mouseovers, and form submissions. Example:
document.getElementById("myButton").addEventListener("click", function() {
alert("Button clicked!");
});
In summary, JavaScript code is a mix of variables, data types, operators, control flow statements, functions, and DOM manipulation. It's a versatile language that enables dynamic and interactive web experiences.