📝 What You’ll Learn

• What JavaScript statements are
• Types of statements commonly used
• How statements execute
• Best practices and common pitfalls

📄 What Is a JavaScript Statement?

A JavaScript statement is a single instruction that the browser executes. Think of it like a sentence in English — each statement tells the browser to do something.

let x = 5;
console.log(x);

Each line above is a statement: one declares a variable, the other prints it.

🔄 Types of Statements

Here are the most common types of statements in JavaScript:

1. ✅ Declaration Statements

Used to declare variables:

let name = "Alex";
const age = 30;

2. 🧠 Expression Statements

These evaluate an expression:

x = 5 + 10;

3. 📢 Output Statements

Used to display information:

console.log("Hello!");

4. 🧩 Conditional Statements

Control decision-making:

if (x > 10) {
  console.log("x is greater than 10");
}

5. 🔁 Looping Statements

Used for repeating tasks:

for (let i = 0; i < 3; i++) {
  console.log(i);
}

🧱 Multiple Statements on One Line

JavaScript allows you to write multiple statements on one line, separated by a semicolon (;):

let a = 1; let b = 2; console.log(a + b);

While valid, this is not recommended for readability.

🚫 Statement Blocks

A block is a group of statements wrapped in {}. Blocks are used in functions, conditionals, loops, etc.

{
  let message = "Hi!";
  console.log(message);
}

⚠️ Common Mistakes

• Forgetting the semicolon at the end of a statement (JavaScript usually handles it, but not always predictably)
• Not wrapping multiple statements inside {} when required
• Misunderstanding expressions vs. statements (e.g., trying to declare a variable inside a conditional expression)

📘 Recap

• A statement is a complete instruction for the browser
• JavaScript has many types: declarations, expressions, loops, conditionals, etc.
• Use semicolons to separate statements, even when JavaScript sometimes allows you to skip them
• Group related statements in blocks {} for structure