<?php
header('content-type:text/html;charset=utf-8');
$score=0;
$score=$_POST[score];
if($score>=0 && $score<60){
   echo '不及格';
}else if($score>=60 && $score<80){
   echo '及格';
}
else if($score>=80 && $score<90){
   echo '良好';
}
else if($score>=90 && $score<100){
   echo '优秀';
}
else if( $score<0){
   echo '你学你吗呢';
}else{
   echo '作弊天谴';
}
?>

错误提示码： Notice: Use of undefined constant score - assumed 'score' in D:\PHP\22.php on line 4