PHP Variables are being 'lost' upon HTML Form submission - php

Question

I'm relatively new to the web development scene and have been assigned with creating a website capable of logging calls.
I have used a HTML form to achieve this - I have made many of these in the past, but have never encountered this issue before.
My page contains 3 buttons: one to log a call, one to forward a call, and one to view all call logs. I achieve this by using an onclick method in the buttons:
<button type=submit value=log onclick="window.location.href='reception.php?log=1';">Log a call.</button>
And then using PHP GET to display the appropriate content on the rest of the page.
try {
$log = $_GET["log"];
}
catch(Exception $ex) {
die();
}
if($log) {
?>
// create form
This works perfectly, and I have created my form as below.
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post" name="log">
<p>
<label>Call date: </label>
<input type="date" name="date" value=<?php echo date("Y-m-d"); ?>>
<span class="error"><sup> <?php echo $dateErr; ?></sup></span>
</p>
<br>
<p>
<label>Does the client have a contract?</label>
<select name="contract">
<option value="default" selected disabled>Please select...</option>
<option value="true">Yes</option>
<option value="false">No</option>
</select>
<span class="error"><sup> <?php echo $contractErr; ?></sup></span>
</p>
<br>
<p>
<label>Client forename:</label>
<input type=text name="fname" <?php if(isset($fname)) echo "value='".$fname."'";?>>
<span class="error"><sup> <?php echo $fnameErr; ?></sup></span>
</p>
<br>
<p>
<label>Client surname:</label>
<input type=text name="sname">
<span class="error"><sup> <?php echo $snameErr; ?></sup></span>
</p>
<br>
<p>
<label style="position: relative; top: -135px;">Client enquiry:</label>
<textarea name=enq style="font-size: 14px; height: 150px; width: 300px;"></textarea>
<span class="error"><sup> <?php echo $enqErr; ?></sup></span>
</p>
<br>
<p>
<button type=submit name=submit value=submit style="position:relative; right: -115px; height:40px; width: 100px;">Submit</button>
</p>
It works just fine. However, the issue comes when submitting the form: for some reason, all PHP variables that I define come up empty when submit is clicked, meaning that any auto-completion / error messages do not show up. As you can see in my form code, as a test I made it autofill the "fname" field if the user has already set it, but it does not work.
Here is my PHP for validation (it is not complete yet, I just wanted to do all of the 'isset' checks first):
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if(isset($_POST["submit"])) {
$go = true;
$query = "INSERT INTO callLog VALUES(NULL, '";
if(empty($_POST["date"])) {
$dateErr = "* Please enter a date.";
$go = false;
}
else {
$query .= date('Y-m-d', strtotime($_POST["date"]))."', ";
}
if(empty($_POST["contract"])) {
$contractErr = "* Please select 'Yes' or 'No'.";
$go = false;
}
else {
$contract = test_input($_POST["contract"]);
if($contract == "Yes") {
$contract = "TRUE";
}
else {
$contract = "FALSE";
}
$query .= $contract.", '";
}
if(empty($_POST["fname"])) {
$fnameErr = "* Please enter a forename.";
$go = false;
}
else {
$fname = test_input($_POST["fname"]);
$query .= $fname."', '";
}
if(empty($_POST["sname"])) {
$snameErr = "* Please enter a surname.";
$go = false;
}
else {
$sname = test_input($_POST["sname"]);
$query .= $fname."', '";
}
if(empty($_POST["enq"])) {
$enqErr = "* Please enter an enquiry.";
$go = false;
}
else {
$query .= $enq."');";
}
if($go) {
$conn->query($query);
header('Location: reception.php');
}
?><script>
$(document).ready(function() {
window.location.href='reception.php?log=1';
});
</script><?php
}
}
The JS at the end is simply so that the page redirects to the call log form page once the data has been submitted, rather than having to click the 'call log' button again.
I'm completely at a loss as to why this doesn't work. Aside from the 'GET' method to display the page, I've done everything as I have in the past which has worked fine. Is it the 'GET' method interfering, or am I missing something?
I have seen that potentially trying something such as Ajax to handle the submission to see if it will work is a possibility, but I am not too familiar with JQuery (knowing only the basics) and do not know how to work with Ajax.
Thanks!

Answer 1

You're highjacking the form submission. You're onclick="window.location.href='reception.php?log=1';" just makes a GET request to that page, not a POST to your form action.