Calling php file from form - php

Question

I have an HTML form that I need to call a php script upon pressing submit but can't work out why the script isn't being executed.
<form action="update.php" method="POST">
<input name="id" type="hidden" value="id"/>
<input name="subArea" type="text" placeholder="Sub Area (optional)"/>
<label><textarea name="description" rows="2" cols="80" placeholder="Description" ></textarea></label>
<label><input type="radio" name="markNA[]" value ="markNA"/> N/A? </label>
<input class = "btn-testname" type="submit" value="Change" name="update"/>
</form >
I don't need the page to reload when pressing the button (so want to avoid Ajax) It was my understanding that the method above will execute the script?
update.php
<?php
include ("databaseLogin.php");
// Create connection to Database
$con = mysqli_connect('localhost',$dbuser,$dbpass,$dbname);
if (!$con)
{
die('Could not connect: ' . mysqli_error($con));
}
// Sql Query
$sql = "INSERT INTO `table_tests` (`active`, `description`)
VALUES (1, 'newstuff')";
mysqli_query($con, $sql);
?>
EDIT 1: I excluded the bringing in of the POST vars just to simplify the php code (and hard coded them into the sql query)
If I'm just missing a stupid syntax error I apologise.

Answer 1

**Try this**
<form action="update.php" method="POST">
<input name="id" type="hidden" value="id"/>
<input name="subArea" type="text" placeholder="Sub Area (optional)"/>
<label><textarea name="description" rows="2" cols="80" placeholder="Description" ></textarea></label>
<label><input type="radio" name="markNA" value ="markNA"/> N/A? </label>
<input class = "btn-testname" type="submit" value="Change" name="update"/>
</form >
<?php
include ("databaseLogin.php");
// Create connection to Database
$con = mysqli_connect('localhost',$dbuser,$dbpass,$dbname);
if (!$con)
{
die('Could not connect: ' . mysqli_error($con));
}
$description = $_POST['description'];
$active= $_POST['markNA'];
$id= $_POST['id'];
// Sql Query
$sql = "INSERT INTO `table_tests` (`active`, `description`,`id`)
VALUES ('$active', '$description','$id')";
mysqli_query($con, $sql);
?>

Answer 2

You have to reload the page or atleast go to another page, PHP is a server sided language so it cant make realtime changes. if you want to do that you have to use javascript.
but the way you are using now you can get the variables from this page in update.php:
$description = $_POST["description"];
If you have that code on update.php the text filled in the description textbox will be saved as the variable $description so you can validate forms for example
======================
EDIT
To get the values of for example the textbox 'description' you can use:
document.getElementById("searchTxt").value;
So if you want to get it on a button click you do :
<script type="text/javascript">
function check () {
document.getElementById("description").value;
}
</script>
<button onclick="check()"></button>
Here you get the value of the field where ID="description"
There are ways you can get it by name but I always rather use ID
document.getElementsByName('description')[0].value
the code above gives you the first element with the name description