find out how request is issued - post

Question

On a site it offers the option of changing your last name, to confirm this it sends a confirmation link to your email.
My question is, how do i figure out how the request is made (if it's POST or GET)? I monitored with live http headers, tamper data, fiddler and burp suite but all have shown there is 0 traffic. When i check my email, i have received the confirmation link.
Here is the html source code of the change lastname button:
<form>
<div class="m-lastname-updated">
<div class="m-h3">One more step</div><p>We have sent you a confirmation email. To change your last name click the sent link in your email!</p>
</div><div class="m-field m-lastname"><div class="m-h3">Last Name</div>
<span class="m-error"></span>
<input type="text" maxlength="100" class="m-input" name="lastname">
<p>Your last name is never shared</p></div><button style="display: inline-block;">Change</button>
</form>
Thanks to anyone who can help me understand how this request is made.
The url this is available on is in this example, http://example.com/profile/.

Answer 1

When a form is submitted, the request is done by default with method="GET" if the method is not specified as method="POST".
To see this, form example, if you use PHP script lastname.php as action:
<?php
echo "<pre>
\$_GET:";
print_r($_GET);
echo "</pre>";
echo "<pre>
\$_POST:";
print_r($_POST);
echo "</pre>";
?>
<form>
<div class="m-lastname-updated">
<div class="m-h3">One more step</div><p>We have sent you a confirmation email.
To change your last name click the sent link in your email!</p>
</div><div class="m-field m-lastname"><div class="m-h3">Last Name</div>
<span class="m-error"></span>
<input type="text" maxlength="100" class="m-input" name="lastname">
<p>Your last name is never shared</p></div><button style="display: inline- block;">Change</button>
</form>
You will see something like this:
$_GET:Array
(
[lastname] => mygod
)
$_POST:Array
(
)
$_GET is filled while $_POST contains no elements.