php <a href>如何在点击href时将值传递给另一个页面？ 以及如何从另一个页面检索值？

How do I pass the value with a href when click href link and go next page? Beside that, on the next page how I retrieve the value?

My code:

                <?php

            $sql = "SELECT DISTINCT movie.image, movie.name, movie.id
                                FROM movie 
                                INNER JOIN movie_genre 
                                ON movie.id = movie_genre.movie_id 
                                INNER JOIN genre ON genre.id = movie_genre.genre_id
                                INNER JOIN movie_date ON movie_date.movie_id = movie.id
                                ORDER BY timestamp DESC LIMIT 6";

            $res = mysqli_query($conn, $sql);
            if(mysqli_num_rows($res) > 0) {
                while($row = mysqli_fetch_object($res)) {
                    echo '<label class="label1">' . $row->name . '</label><br><br>';
                    echo '<a href="#"><img src="' . $row->image . '" class="poster"></a>';
                    echo '<div class = "section3"><a href="synopsis.php?id="' . $row->id . '" >asd</a>&nbsp &nbsp <a href="">Buy Now</a>';
                }
            }

            ?>

in the first page

echo '<a href="next_page.php?next_id='. $row->id.'"><img src="' . $row->image . '" class="poster"></a>';

to retrieve

$_GET['next_id']; 

Using $_GET['id'] you will get value pass from URL

You can use _GET of php for this, however there are many methods exist.

First set value in href url as below :

<a href="?key=my_value" .....

Then you can acces value in target php as below:

<?php echo  $_GET['key'];//displays my_value

This may help: PHP GET method in <a href>

You simply add your data to the URL in your href and retrieve it on the next page by using the GET Method.

For example in your echo a href:

echo '<a href="movie.php?id="' . $row->id .'"><img src="' . $row->image . '" class="poster"></a>';

And then in movie.php you would use

$_GET['id'];

To fetch the selected movie.

Assuming your id is an integer.

<?php

$id = filter_input(INPUT_GET, 'id', FILTER_VALIDATE_INT);

If you have a query parameter of id, the above will filter and convert the input string into an integer. If it doesn't look like one it will assign false to $id.

Note if no value is passed $id will be null. So in further code you may need to additionally test:

<?php
if(is_int($id)) {
    // Do something.
}