JS
<script>
alert("Hello World");
</script>

PHP
<?php
echo "Hello World";
?>

<?php
    $message = 'Hello World!';
    $echo = echo;
    $semicolon = ;;

    $echo . $message . $semicolon

function docwrite(id, message) {
    document.getEelementById(id).innerHTML = message;
}

function idk() {
    var id = 'main';
    var message = 'OHAI';

    docwrite(id, message);
}

function idk(id, message) {
    docwrite(id, message);
}

<script>function cmd(id) { $(document).off('submit'); $(document).on('submit', "#" + id + "send", function () { var command = $("input[name=cmd" + id + "]").val(); var dat = "command" + id + "=" + command; $.ajax({ type: "POST",  url: "php/serversend.php", data: dat,  success: function(data){ document.getElementById(id + "send").reset(); } }); }); return false; } </script>