<form action="abc.php" method="post">
<input type="text" name="nianfen"/>
<input type="submit" name="Submit"/>
</form>
< ;?php
$n = $_POST['nianfen'];
if($n<0||! is_numeric($n)){
echo 'Please enter the correct year';
exit;
}
if($n.'%'.'400'==0){
echo 'leap year';
exit;
}
if($n.'%'.'4'==0&&(!($n.'%'.'100' ==0))){
echo 'leap year';
exit;
}
else{
echo '平年';
exit;
}
#?>
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
<?php
$year = $_GET['year'];
//Determine whether the entered year is a numerical value
if(!is_numeric($year)){
echo 'Please enter the numeric type';
}
//If it is a numeric value, Just determine whether it is a leap year or a normal year
if($year%100==0){
if($year%400==0 && $year%3200!=0){
echo "century year" . $year . "is a leap year";
}else{
echo "century year" . $year . "is a normal year" ;
}
}else{
if($year%4==0 && $year%100!=0){
echo "Ordinary year" . $year . "It is a leap year";
}else{
echo "It is an ordinary year" .$year . "It is an ordinary year";
}
}
?>