編集：簡単な例
<form>を実行します 、検証および1つへの挿入 ファイル、たとえばform.php ：
<? // check if FORM has been posted
$posted = isset($_POST['submit']);
if ($posted) { // form has been posted...
// validate input
if (!isset($_POST['item']) || strlen(trim($_POST['item'])) == 0)
$error['item'] = "please insert an item-name!";
if (!isset($_POST['price']) || !is_numeric($_POST['price']))
$error['price'] = "please enter a valid price!";
// ready for input?
if (!isset($error)) { // no $error --> go insert!
// I'll do the db-operation with PDO and a prepared statement.
// this is cool, easy and safe. LEARN IT!
$sql = "INSERT INTO table (item,price) VALUES (:item,:price)";
$insert = $db->prepare($sql);
$insert->execute(array(
':item' => $_POST['item'],
':price' => $_POST['price']
));
} // $error
} // submit
?>
さて、<body>で 同じの ページ...
<? // check whether to display confirmation or form...
if ($posted && !isset($error)) {
// form was sent AND no error --> confirm
?>
<h1>Confirmed!</h1>
<p>Your data has been sent, thank you very much!</p>
<a href="somepage.php">go to somepage</a>
<?
} else {
// form not sent or errors --> display form
?>
<h1>Please enter data</h1>
<? // display error-message, if there's one:
if (isset($error)) {
$output = "";
foreach ($error as $field => $msg)
$output .= (strlen($output) > 0?', ':'') . "[$field]: $msg";
echo "<p>There were errors: $output</p>";
} // $error
?>
<form method="post">
<!-- if the form has been sent, bring back the field's value from $_POST -->
<p>item-name: <input type="text" name="item"
value="<?=($posted?$_POST['item']:'')?>" /></p>
<p>price: <input type="text" name="price"
value="<?=($posted?$_POST['price']:'')?>" /></p>
<p><input type="submit" name="submit" value="submit" /></p>
</form>
<?
} // submit & $error
?>
ternary-operatorの使用を参照してください valueを設定するため -<input>の属性 -要素：
(<condition>?<what to do if true>:<what to do if false>)