en.javascript.info/1-js/02-first-steps/11-logical-operators/5-alert-and-or/solution.md

The answer: 3.

alert( null || 2 && 3 || 4 );

The precedence of AND && is higher than ||, so it executes first.

The result of 2 && 3 = 3, so the expression becomes:

null || 3 || 4

Now the result if the first truthy value: 3.