// Runs. // The result of -1 || 0 = -1, truthy if (-1 || 0) alert( 'first' ); // Doesn't run // -1 && 0 = 0, falsy if (-1 && 0) alert( 'second' ); // Executes // Operator && has a higher precedence than || // so -1 && 1 executes first, giving us the chain: // null || -1 && 1 -> null || 1 -> 1 if (null || -1 && 1) alert( 'third' );