php string to javascript code example

Example 1: php into javascript

$str = <<<MY_MARKER
<script type="text/javascript">
  document.write("Hello World!");
</script>
MY_MARKER;

echo $str;

Example 2: js to php

const toSend = {
            x: 10, 
            y: 12
        };
        const jsonString = JSON.stringify(toSend);
        const xhr = new XMLHttpRequest();

        xhr.open("POST", "file.php");
        xhr.setRequestHeader("Content-Type", "application/json");
        xhr.send(jsonString);
//php: 
$request = file_get_contents("php://input");
$obj = json_decode($request);
var_dump($obj);