ปกติถ้าเราใส่ตัวแปรในตาราง เมื่อไฟล์ถูกอ่านมันจะแสดงตารางแต่ไม่แสดงค่าตัวแปรจนกว่าจะ submit สามารถแก้ได้โดยกำหนด ค่า
To create a PHP script that does not show a table until a form is submitted, you can use conditional statements and HTML markup.
<?php
if(isset($_POST['submit'])) { // check if form is submitted
// process form data and generate table
$table_data = "<table><thead><tr><th>Header 1</th><th>Header 2</th></tr></thead><tbody><tr><td>Data 1</td><td>Data 2</td></tr></tbody></table>";
} else {
// form not submitted, so do not generate table
$table_data = "";
}
?>
<!DOCTYPE html>
<html>
<head>
<title>PHP Form Example</title>
</head>
<body>
<form method="POST">
<!-- form fields here -->
<input type="submit" name="submit" value="Submit">
</form>
<?php echo $table_data; ?>
</body>
</html>
เมื่อเปิดไฟล์จะแสดงแค่ปุ่ม submit และเมื่อ submit จึงจะแสดงตาราง
สองตัวนี้เหมือนกัน
if ($_SERVER['REQUEST_METHOD'] == 'POST') { // น่าเชื่อถือกว่า
if(isset($_POST['submit'])) {Both isset($_POST['submit']) and $_SERVER['REQUEST_METHOD'] == 'POST' can be used to check if a form has been submitted in PHP, but they work in slightly different ways.
isset($_POST['submit']) checks if a specific form field with the name submit has been submitted with a non-empty value. This approach relies on the form field being present and correctly named, so it may not work if the form is modified or if the field name is changed.
On the other hand, $_SERVER['REQUEST_METHOD'] == 'POST' checks if the HTTP request method is POST, which is the method used to submit form data. This approach is more reliable because it doesn’t rely on a specific form field being present or correctly named. It also helps to prevent CSRF attacks (Cross-Site Request Forgery) by ensuring that the form data is submitted via an authorized request method.
In general, it’s recommended to use $_SERVER['REQUEST_METHOD'] to check if a form has been submitted in PHP because it’s more secure and reliable.