Validate checkboxes values in PHP - php

Question

I have a group of checkboxes with different values each. I want to assign their values in php variables which i'm going to send to database. The main problem is that i don't know how to check inside the php code if the values of selected items matching their default values which i setup in the html (apple == apple, samsung == samsung) and so on. This is because someone can just change the input value inside the console and insert whatever he likes in my DB. Any ideas how i can sort this out. Many thanks!
<form action="" method="POST">
<label for="apple">Apple</label>
<input id="apple" type="checkbox" name="myCheckBoxes[]" value="Apple">
<label for="samsung">Samsung</label>
<input id="samsung" type="checkbox" name="myCheckBoxes[]" value="Samsung">
<label for="lenovo">Lenovo</label>
<input id="lenovo" type="checkbox" name="myCheckBoxes[]" value="Lenovo">
<label for="google">Google Pixel</label>
<input id="google" type="checkbox" name="myCheckBoxes[]" value="Google Pixel">
<button type="submit" name="submit">Send</button>
</form>
PHP Code:
if (isset($_POST['submit'])) {
$checkBoxes = $_POST['myCheckBoxes'];
$numberSelected = count($checkBoxes);
if ($numberSelected > 3) {
echo 'Please select only 3 from the options';
} else {
for ($i = 0; $i < $numberSelected; $i++) {
$option1 = $checkBoxes[0];
$option2 = $checkBoxes[1];
$option3 = $checkBoxes[2];
}
echo 'You have selected', ' ', $option1, ' ', $option2, ' ', $option3;
}
}

Answer 1

You can define a constant array with the allowed values, then only use values from that array when they correspond to the input value.
const ALLOWED_VALUES = [
"apple" => "Apple",
"samsung" => "Samsung",
"lenovo" => "Lenovo",
"google pixel" => "Google Pixel",
];
if (isset($_POST['submit'])) {
$checkBoxes = $_POST['myCheckBoxes'];
$options = [];
if (count($checkBoxes) > 3) {
echo 'Please select only 3 from the options';
} else {
foreach($checkBoxes as $box) {
$box = strtolower(trim($box));
if(array_key_exists($box, ALLOWED_VALUES)){
$options[] = ALLOWED_VALUES[$box];
}
}
$option1 = (array_key_exists(0, $options))? $options[0]: null;
$option2 = (array_key_exists(1, $options))? $options[1]: null;
$option3 = (array_key_exists(2, $options))? $options[2]: null;
echo 'You have selected', ' ', $option1, ' ', $option2, ' ', $option3;
}
}
The code above will accept "APPLE" but will use "Apple" anything not found or empty will be set to null. Run it live here: https://onlinephp.io/c/8409e

Answer 2

you can do it through the help of or (||) , and (&&) operator in else part of if condition.
if(($option1=='Apple' || $option1=='Samsung' || $option1=='Lenovo'||$option1=='Google Pixel') && ($option2=='Apple' || $option2=='Samsung' || $option2=='Lenovo'||$option2=='Google Pixel') && ($option3=='Apple' || $option3=='Samsung' || $option3=='Lenovo'||$option3=='Google Pixel')){
echo 'You have selected', ' ', $option1, ' ', $option2, ' ', $option3;
}else{
echo"Please select suggested checkbox";
}