如果（isset（$ _ GET ['确认']）），我在这里做错了什么？

My Get confirm isn't triggering the query? Can anyone see what I'm doing wrong?

url: http://www.example.co.uk/registerinterest.php?productid=125&confirm=Confirm

<div class="confirminterest">
     <form action="registerinterest.php?productid=' . $productid . '" method="post" enctype="multipart/form-data">
       <input name="confirm" type="submit" id="confirm" value="Confirm" />
     <input name="cancel" type="button" id="cancel" value="Cancel" /></form>
   </div>

 if (isset($_GET['Confirm'])) {
         $addinterest = mysql_query("INSERT INTO tm_credits_spent (fk_customer_id, fk_product_id, int_credits_spent) VALUES('$pid','$productid','$adminfee')") or die (mysql_error());
}

You are looking for GET data when your form uses the POST method. Since you are inserting data into a database, POST is correct, so replace $_GET with $_POST.

You are also looking for Confirm when your button is named confirm. PHP is case sensitive, so replace that too.

$_POST['confirm']

You also appear to be at risk of SQL injection.

Your form is sending POSTdata, not GET. Either change the form's method, or check for $_POST['confirm'].

You have set the method to be post. Try with $_POST['Confirm'];

Adding my own answer as the others are missing that the name of your input is "confirm", not "Confirm" (that's its value).

So you must check isset() for $_POST['confirm'], not $_POST['Confirm'] or $_GET['confirm'].

In both your GET string, and your form (which uses POST), the field is "confirm", not "Confirm". Note the lower case 'c'.

Try: if (isset($_GET['confirm'])) { (or if (isset($_POST['confirm'])) {).

you are using php variable in html may be that's the issue replace this;

<form action="registerinterest.php?productid=' . $productid . '" method="post" enctype="multipart/form-data">

with

<form action="registerinterest.php?productid=' .<?php $productid ?>. '" method="post" enctype="multipart/form-data">

and yes use $_POST['confirm'] for condition.