JavaScript If...Else

Definition: An if statement runs code only when a condition is true. else if and else let you choose between several outcomes. The condition goes in round brackets, the code in curly braces.

Example 1 — simple if

let age = 20;
if (age >= 18) {
  console.log("You are an adult");
}

Example 2 — if...else

let age = 15;
if (age >= 18) {
  console.log("Adult");
} else {
  console.log("Minor");
}

Example 3 — else if chain

let score = 75;
if (score >= 90) {
  console.log("Grade A");
} else if (score >= 70) {
  console.log("Grade B");
} else if (score >= 50) {
  console.log("Grade C");
} else {
  console.log("Fail");
}

Example 4 — the ternary shortcut

For a quick either/or on one line:

let age = 20;
let type = age >= 18 ? "Adult" : "Minor";
console.log(type);

💡 Try it: change score and run again to watch each branch fire.