Website launch countdown in milliseconds. Counts down from a specific date in PHP and jQuery.

milliseconds_countdown.php

<div id="timer"></div>

<script>
var millis = <?php 
$timestamp = strtotime('2020-07-30');// your launch date
$difference = $timestamp - time();// difference in seconds
echo ($difference * 1000); ?>;

function displaytimer(){
    $('#timer').html(millis);  
}

setInterval(function(){ // counts every millisecond down and updates
    millis -= 1;
    displaytimer();
}, 1);
</script>