Append text from HTML to XML - html

Question

G'day,
As a part of my assignment, I have to store the details entered by a user in a registration form into an XML document.
I have managed to do that BUT the problem is when a new user registers, the old details are over-written with the details of the new user. So, there is ONLY 1 user details in the XML document in the end.
I was wondering if there's any way to save the details of new user while "preserving" the old details.
Any help is appreciated :)
HTML Code -
<form id="rego" name="rego" method="get" action="register2.php">
<table width="719" border="0">
<tr>
<td><div align="right">Email Address</div></td>
<td><label for="email"></label>
<input type="text" name="email" id="email" maxlength="50" /></td>
</tr>
<td width="376"><div align="right">First Name</div></td>
<td width="333"><label for="firstName"></label>
<input type="text" name="firstName" id="firstName" maxlength="15" /></td>
<td><div id="underInput"></div></td>
</tr>
<tr>
<td><div align="right">Last Name</div></td>
<td><label for="lastName"></label>
<input type="text" name="lastName" id="lastName" maxlength="20" /></td>
</tr>
<tr>
<td><div align="right">Phone Number</div></td>
<td><label for="phoneNumber"></label>
<input type="text" name="phoneNumber" id="phoneNumber" maxlength="10" /></td>
</tr>
<tr>
<tr>
<td><div align="right">Password</div></td>
<td><label for="password"></label>
<input type="password" name="password" id="password" maxlength="30" /></td>
</tr>
<tr>
<td><div align="right">Re-type password</div></td>
<td><label for="confirmPassword"></label>
<input type="password" name="confirmPassword" id="confirmPassword" maxlength="30" /></td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
<tr>
<td> </td>
<td><input type="Submit" name="Submit" id="Submit" value="Submit"/><!--onclick="saveForm();"--></td>
</tr>
PHP Code (I'm using DOM) -
<?php
$CustomerEmail = $_GET["email"];
$CustomerFName = $_GET["firstName"];
$CustomerLName = $_GET["lastName"];
$CustomerPhoneNumber = $_GET["phoneNumber"];
$CustomerPassword = $_GET["password"];
$CustomerConfirmPassword = $_GET["confirmPassword"];
$doc = new DomDocument('1.0');
$root = $doc->createElement('customers');
$root = $doc->appendChild($root);
$customer = $doc->createElement('customer');
$customer = $root->appendChild($customer);
$email = $doc->createElement('email');
$email = $customer->appendChild($email);
$valueEmail = $doc->createTextNode($CustomerEmail);
$valueEmail = $email->appendChild($valueEmail);
$fName = $doc->createElement('firstname');
$fName = $customer->appendChild($fName);
$valueFName = $doc->createTextNode($CustomerFName);
$valueFName = $fName->appendChild($valueFName);
$lName = $doc->createElement('lastname');
$lName = $customer->appendChild($lName);
$valueLName = $doc->createTextNode($CustomerLName);
$valueLName = $lName->appendChild($valueLName);
$phone = $doc->createElement('phone');
$phone = $customer->appendChild($phone);
$valuePhone = $doc->createTextNode($CustomerPhoneNumber);
$valuePhone = $phone->appendChild($valuePhone);
$password = $doc->createElement('password');
$password = $customer->appendChild($password);
$valuePassword = $doc->createTextNode($CustomerPassword);
$valuePassword = $password->appendChild($valuePassword);
$confirmPassword = $doc->createElement('confirmpassword');
$confirmPassword = $customer->appendChild($confirmPassword);
$valueConfirmPassword = $doc->createTextNode($CustomerConfirmPassword);
$valueConfirmPassword = $confirmPassword->appendChild($valueConfirmPassword);
$doc->save('customer2.xml');
?>
I apologise for any inconvience.

Answer 1

You need to load your existing file, before creating a new one each time and override the previous.
.....
$doc = new DomDocument('1.0');
if($xml = file_get_contents( 'customer2.xml')){
$doc->loadXML( $xml, LIBXML_NOBLANKS );
$root=$doc->getElementsByTagName('customers')->item(0);
}else{
$root = $doc->createElement('customers');
$root = $doc->appendChild($root);
}
$customer = $doc->createElement('customer');
$customer = $root->appendChild($customer);
.....
$doc->save('customer2.xml');