checking_null.php

<?php

$good = json_decode('{ "label": "This is valid JSON", "value": 5 }' );
$bad  = json_decode('{ "label": This is invalid JSON, "value": 5 }' );

if( is_null( $good ) ) {
        echo "Couldn't parse good JSON\n";
}
else {
        echo $good->value . "\n";
}

if( is_null( $bad ) ) {
        echo "Couldn't parse bad JSON\n";
}
else {
        echo $bad->value . "\n";
}