Question mark and colon in JavaScript

Question

I came across the following line

hsb.s = max != 0 ? 255 * delta / max : 0;

What do the ? and : mean in this conte

Answer 1

Properly parenthesized for clarity, it is

hsb.s = (max != 0) ? (255 * delta / max) : 0;

meaning return either

• 255*delta/max if max != 0
• 0 if max == 0