Undefined Index when passing data to different HTML5 page - php

Question

The following is one of my HTML pages.
<form id="regForm" method="post" action="enquiry_process.php" novalidate="novalidate">
<fieldset>
<legend>Personal Details</legend>
<label>First Name:</label>
<input type="text" name="owner" id="owner" /><br />
<label>Last Name:</label>
<input type="text" name="owner2" id="owner2" /><br />
</fieldset>
<p>
<input type="Submit" onclick="validateForm()"/>
<input type="Reset" value="Reset" />
</p>
</form>
The following is my 2nd HTML page.
<form id="bookForm" method="post" action="view_enquiry.php">
<?php
$fname = $_POST['owner'];
$lname = $_POST['owner2'];
?>
<input type="hidden" name="owner" value="<?php echo $fname; ?>">
<input type="hidden" name="owner2" value="<?php echo $lname; ?>">
<fieldset>
<legend>User Details</legend>
<p>Your First Name: <span id="confirm_fname"></span></p>
<p>Your Last Name: <span id="confirm_lname"></span></p>
<input type="submit" name="submit" value="Confirm Booking" />
<input type="button" value="Cancel" id="cancelButton" onclick="cancelBooking()" />
</fieldset>
The functions you see like validateForm() and cancelBooking() are Javascript functions that validate my form or return the user from the 2nd page to the 1st and I believe they have nothing to do with my question.
When I click submit on the first HTML page, it should pass on the value of the owner and owner2 to the 2nd page right?
I keep on getting Undefined index and after looking around, it seems like I have to use isset() or empty() in my PHP, but this seems to only mask my notices but does not actually fix it? When I just add isset(), it ends up giving my 3rd page Undefined Variable. The method on my forms are already post.
Is there another problem here? Thank you.
EDIT: The following is are my relevant Javascripts.
ValidateForm:
function validateForm(){
"use strict";
gErrorMsg = "";
var nameOK = chkOwnerName();
var nameOK2 = chkOwnerName2();
var isAllOK = (nameOK && nameOK2);
if(isAllOK){
isAllOK = storeBooking();
}
else{
alert(gErrorMsg);
gErrorMsg = "";
}
return isAllOK;
}
Storebooking:
function storeBooking() {
"use strict";
sessionStorage.firstname = document.getElementById("owner").value;
sessionStorage.lastname = document.getElementById("owner2").value;
window.location = "enquiry_process.php";
}
I have another function called getbooking that runs with the condition window.onload
function getBooking(){
//if sessionStorage for username is not empty
if((sessionStorage.firstname != undefined)){
//confirmation text
document.getElementById("confirm_fname").textContent = sessionStorage.firstname;
document.getElementById("confirm_lname").textContent = sessionStorage.lastname;
}
chkOwnerName and chkOwnerName2 are functions that validate the form with patterns and I don't think they're relevant.
I also updated my 2nd HTML page with Javascript related contents because I assumed it wasn't relevant at first.

Answer 1

You can debug with below code by adding it in your 2nd form page.
echo "<pre>"; print_r($_POST); die;
If your form data is not going to your 2nd form then Array() will come as empty.

Answer 2

u can try by print_r($_REQUEST[]); on second form top page (enquiry_process.php) , i hope the both the form is in same folder and name of second form page is "enquiry_process.php" .
Since u r sending data using post form u should be able to retrieve it by print_r($_POST); or print_r($_REQUEST);

Answer 3

"if(empty($var))" and "if(isset($var))" are conditions, they check something and execute code within "{}" if the test returns true. So they don't 'fix' problems.
Your script worked fine for me without your js. Maybe the problem.
Just try your code step by step. You will find what's wrong.