php根据日期显示所在星座的方法

<?php 
function zodiac($dob){ 
  $dob = date("m-d", strtotime($dob)); 
  list($month,$day) = explode("-",$dob); 
  if(($month == 3 || $month == 4) && ($day > 22 || $day < 21)){ 
    $zodiac = "aries"; 
  } 
  elseif(($month == 4 || $month == 5) && ($day > 22 || $day < 22)){ 
    $zodiac = "taurus"; 
  } 
  elseif(($month == 5 || $month == 6) && ($day > 23 || $day < 22)){ 
    $zodiac = "gemini"; 
  } 
  elseif(($month == 6 || $month == 7) && ($day > 23 || $day < 23)){ 
    $zodiac = "cancer"; 
  } 
  elseif(($month == 7 || $month == 8) && ($day > 24 || $day < 22)){ 
    $zodiac = "leo"; 
  } 
  elseif(($month == 8 || $month == 9) && ($day > 23 || $day < 24)){ 
    $zodiac = "virgo"; 
  } 
  elseif(($month == 9 || $month == 10) && ($day > 25 || $day < 24)){ 
    $zodiac = "libra"; 
  } 
  elseif(($month == 10 || $month == 11) && ($day > 25 || $day < 23)){ 
    $zodiac = "scorpio"; 
  } 
  elseif(($month == 11 || $month == 12) && ($day > 24 || $day < 23)){ 
    $zodiac = "sagittarius"; 
  } 
  elseif(($month == 12 || $month == 1) && ($day > 24 || $day < 21)){ 
    $zodiac = "cpricorn"; 
  } 
  elseif(($month == 1 || $month == 2) && ($day > 22 || $day < 20)){ 
    $zodiac = "aquarius"; 
  } 
  elseif(($month == 2 || $month == 3) && ($day > 21 || $day < 21)){ 
    $zodiac = "pisces"; 
  } 
  return $zodiac; 
} 
echo zodiac('1986-07-22'); //valid strtotime date 
?>