PHP入门必读(17){ print "The site is busy right now!"; } elseif ($user_count > 100) { print "The site is sort of active right now!"; } else { print "The site is lonely - only $user_count user logged on."; } 運算元(operator)利用的最高指導原則同樣也可以運用在控制結構上面. 你還可以使用 switch, do...while,甚至是 ?: 程式結構。