If Statements | Learn Computer Academy

If Statements

An if statement lets your program make a decision — run one block of code if a condition is true, and optionally a different block if it's false.

Basic if

let temperature = 35;

if (temperature > 30) {
  console.log("It's hot today.");
}

if / else

let age = 15;

if (age >= 18) {
  console.log("You can vote.");
} else {
  console.log("Not old enough to vote yet.");
}

if / else if / else

Chain multiple conditions when there are more than two possible outcomes.

let score = 72;

if (score >= 90) {
  console.log("Grade: A");
} else if (score >= 75) {
  console.log("Grade: B");
} else if (score >= 60) {
  console.log("Grade: C");
} else {
  console.log("Grade: F");
}
// Output: Grade: C

Only the first matching condition runs — once one branch is chosen, JavaScript skips the rest, even if a later condition would also have been true.