How do you write conditional statements in JavaScript, and what operators do conditions use?

You use if / else to run code only when a condition is true, building conditions from comparison operators (===, >, ...) and logical operators (&&, ||, !).

A conditional lets a program make decisions: run one block of code when a condition holds, and (optionally) another when it doesn't.

// Light is bright between 8 and 20 o'clock, otherwise dim
if (zeit >= 8 && zeit <= 20) {
    licht = 'hell';     // condition true
} else {
    licht = 'schwach';  // condition false
}

(Here zeit is German for "time" and licht for "light" — the logic is what matters.)

Conditions are built from comparison operators, which return a Boolean:

And logical operators combine several conditions:

A key gotcha: prefer === over ==. The loose == coerces types before comparing, leading to oddities like 0 == '' being true. The strict === compares value and type, which is almost always what you actually want.