php - How to make a text box change depending on a dropdown menu

Question

I would like to know how to make a text box change according to a drop down menu. So for example ...

<form action="index.php" method="POST">
<p>Product:</p>
<select id = "myPRODUCTS">
<option value = "Apple">Apple</option>
<option value = "Orange">Orange</option>
<option value = "Mango">Mango</option>
</select>
<p>Price:</p><input type="text" name="Price" readonly="readonly" />

So I want the price text box to change if I have selected Apple I want it to be ￡0.45 or if I select orange I want it to be ￡0.50 and so on. How would I do this?

Thanks in advance, Marek

Answer 1

This code shows how you can accomplish what you seek.
As others have mentioned, it's not exactly the most secure / efficient way to do this, especially if you're dealing with real money, but all you have to do to get this to work is add jquery to your html file with <script src="http://code.jquery.com/jquery-latest.min.js"></script>

$('#myPRODUVTS').on('change', function() {
 fruit = $(this).val();
    if (fruit == 'Apple') {
        $('#Price').val('￡0.45');
    }
    if (fruit == 'Orange') {
        $('#Price').val('￡0.50');
    }
    if (fruit == 'Mango') {
        $('#Price').val('￡0.65');
    }
});

http://jsfiddle.net/LtBh6/ this shows the code in action with your example.