The else Branch

An if statement runs its block only when the condition is true. Often you also want to do something when it's false. That's what else (otherwise) is for:

const temperature = 12;
if (temperature > 25) {
    console.log("Take a cap");
} else {
    console.log("Take a jacket");
}

This prints:

Take a jacket

The condition temperature > 25 is false, so the program skips the first block and runs the block after else. The two blocks are called branches: like a path that splits in two, the program always takes exactly one of them. If the condition is true, it takes the first branch; otherwise, the second. It never runs both, and it never skips both.

else has no condition of its own: it takes every case the if didn't. It can't stand on its own, either. It always comes right after the closing } of an if block. A semicolon between them, }; else {, splits them apart, and the program ends with an error: SyntaxError: Unexpected token 'else'.

We write } else { on one line. You may also see else on a new line under the }; JavaScript accepts both.