如何将表单发布到两个不同的页面并在提交的页面中使用表单数据？

Question

What I am trying to do is I have a form which inserts data into a table. But now I want to add a preview button to the form to show a preview of the data to be inserted and uploader can check the formatting he has done before inserting data.

Now I want to know how to submit form to two different pages and use the form data.

I am confused as Using action attribute of form will make both buttons to POST to same page.

I have also tried code below, but it will also fail if the data is too much and as data3 is paragraph and can have long essay data

if( $_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['preview']) ){
    $data1 = trim($_POST['data1']);
    $data2 = trim($_POST['data2']);
    $data3 = trim($_POST['data3']);
    header("location: preview.php?preview=true&data1=$data1&data2=$data2&data3=$data3");
    exit();
}

Answer 1

Use a session, and store the post data in an array, or output the variables in a hidden form on preview page.

Example 1:

session_start();

$_SESSION['form_data'] = [
    'data1' => $_POST['data1']
    ...
];

Example 2:

echo '<input type="hidden" name="data1" value="', htmlspecialchars($_POST['data1']), '" />';