- var_dump: documentation ( source)
<?php
$formData = array();
echo 'empty($formData[chain_id]): ';
var_dump(empty($formData['chain_id']));
echo "\n";
echo '$formData[chain_id] === \'0\': ';
var_dump($formData['chain_id'] === '0');
echo "\n";
$formData['chain_id'] = 0;
echo 'empty($formData[chain_id]): ';
var_dump(empty($formData['chain_id']));
echo "\n";
echo '$formData[chain_id] === \'0\': ';
var_dump($formData['chain_id'] === '0');
echo "\n";
$formData['chain_id'] = 1;
echo 'empty($formData[chain_id]): ';
var_dump(empty($formData['chain_id']));
echo "\n";
echo '$formData[chain_id] === \'0\': ';
var_dump($formData['chain_id'] === '0');
echo "\n";