Send value of submit button when form gets posted

I have a list of names and some buttons with product names. When one of the buttons is clicked the information of the list is sent to a PHP script, but I can't hit the submit button to send its value. How is it done? I boiled my code down to the following:

The sending page:

<html>
<form action="buy.php" method="post">
    <select name="name">
        <option>John</option>
        <option>Henry</option>
    <select>
    <input id='submit' type='submit' name = 'Tea'    value = 'Tea'>
    <input id='submit' type='submit' name = 'Coffee' value = 'Coffee'>
</form>
</html>

The receiving page: buy.php

<?php
    $name = $_POST['name'];
    $purchase = $_POST['submit'];
    //here some database magic happens
?>

Everything except sending the submit button value works flawlessly.


The button names are not submit, so the php $_POST['submit'] value is not set. As in isset($_POST['submit']) evaluates to false.

<html>
<form action="" method="post">
    <input type="hidden" name="action" value="submit" />
    <select name="name">
        <option>John</option>
        <option>Henry</option>
    <select>
<!-- 
make sure all html elements that have an ID are unique and name the buttons submit 
-->
    <input id="tea-submit" type="submit" name="submit" value="Tea">
    <input id="coffee-submit" type="submit" name="submit" value="Coffee">
</form>
</html>

<?php
if (isset($_POST['action'])) {
    echo '<br />The ' . $_POST['submit'] . ' submit button was pressed<br />';
}
?>

Use this instead:

<input id='tea-submit' type='submit' name = 'submit'    value = 'Tea'>
<input id='coffee-submit' type='submit' name = 'submit' value = 'Coffee'>