<?php
#Definição de variáveis de data
$dia=date(d);
$mes=date(n);
$ano=date(Y);
#Definição de variáveis de hora
$hora=date(H);
$minutos=date(i);
#Imprime data
echo"$dia/$mes/$ano ";
#Imprime hora
echo"$hora:$minutos";
#Simplificando o script:
$data = date("m/d/y");
$hora = date("H:i:s");
echo"$data<br>";
echo"$hora";
?>
<html>
<head>
<script type="text/javascript">
function doOnSubmit(form){
var currentTime = new Date();
form.timestamp.value=currentTime.toLocaleString();
return true;
}
</script>
</head>
<body>
<form name='MyForm' method='post' onsubmit='return doOnSubmit(this)' >
<input type='text' name='timestamp' value=''>
...
...
...
<input type="submit" value='Submit'>
</form>
</body>
</html>