What are the differences between associative arrays in JavaScript and PHP, and how does this impact the use of json_encode in PHP?

In JavaScript, associative arrays are actually objects, while in PHP, associative arrays are implemented as arrays. This difference can impact the use of json_encode in PHP because when encoding associative arrays in PHP, json_encode will treat them as objects instead of arrays. To ensure that associative arrays are encoded as arrays in PHP, you can use the JSON_FORCE_OBJECT flag when calling json_encode.

$data = array("key1" => "value1", "key2" => "value2");
$json = json_encode($data, JSON_FORCE_OBJECT);
echo $json;