<html>
<header>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title> 線形予測ツール </title>
</header>
<body bgcolor="#e0f0ff">
<?php
$datetime1_str = @$_REQUEST['datetime1'];
$datetime2_str = @$_REQUEST['datetime2'];
$datetime1 = strtotime($datetime1_str);
$datetime2 = strtotime($datetime2_str);
$amount1 = @$_REQUEST['amount1'];
$amount2 = @$_REQUEST['amount2'];
$amount3 = @$_REQUEST['amount3'];
//
$datetime1_str = htmlspecialchars($datetime1_str);
$datetime2_str = htmlspecialchars($datetime2_str);
$amount1_str = htmlspecialchars($amount1);
$amount2_str = htmlspecialchars($amount2);
$amount3_str = htmlspecialchars($amount3);
?>
<form>
1: <input type="text" name="datetime1" value="<?php echo $datetime1_str ?>"> : <input type="text" name="amount1" value="<?php echo $amount1_str ?>">
<br />
2: <input type="text" name="datetime2" value="<?php echo $datetime2_str ?>"> : <input type="text" name="amount2" value="<?php echo $amount2_str ?>">
<br />
3: YYYY-mm-dd HH:ii:ss : <input type="text" name="amount3" value="<?php echo $amount3_str ?>"> <input type="submit">
</form>
<?php
if (($datetime1_str !== '') && ($datetime2_str !== '') &&
($amount1 !== '') && ($amount2 !== '') && ($amount3 !== '')) {
$datetime3 = $datetime1 + ($amount3 - $amount1)/($amount2 - $amount1) * ($datetime2 - $datetime1);
echo "YYYY-mm-dd HH:ii:ss = ".date('Y-m-d H:i:s', $datetime3)."<br />\n";
}
?>
</body>
</html>