<script type="text/JavaScript">
var Affiche=document.getElementById("Compte");
function Rebour() {

var date1 = new Date();
var date2 = new Date ("Apr 25 17:45:00 2010"); 
var sec = (date2 - date1) / 1000; 
var n = 24 * 3600; 
if (sec > 0) {
    j = Math.floor (sec / n);
    h = Math.floor ((sec - (j * n)) / 3600);
    mn = Math.floor ((sec - ((j * n + h * 3600))) / 60);
    sec = Math.floor (sec - ((j * n + h * 3600 + mn * 60)));
    Affiche.innerHTML =  + h +":"+ mn +":"+ sec + "  ";
    window.status = "Compte rebours";
}

else {
    Affiche.innerHTML = "Temp Terminés";
    window.status = "Comte rebour fini";
}

tRebour=setTimeout ("Rebour();", 1000);
}
Rebour();
</script>

[color=#FF0000]<?php
$date="Apr 25 17:45:00 2010";
?>[/color]
<script type="text/JavaScript">
var Affiche=document.getElementById("Compte");
function Rebour() {

var date1 = new Date();
var date2 = new Date ([color=#FF0000]<?= $date ?>[/color]); 
var sec = (date2 - date1) / 1000; 
var n = 24 * 3600; 
if (sec > 0) {
    j = Math.floor (sec / n);
    h = Math.floor ((sec - (j * n)) / 3600);
    mn = Math.floor ((sec - ((j * n + h * 3600))) / 60);
    sec = Math.floor (sec - ((j * n + h * 3600 + mn * 60)));
    Affiche.innerHTML =  + h +":"+ mn +":"+ sec + "  ";
    window.status = "Compte rebours";
}

else {
    Affiche.innerHTML = "Temp Terminés";
    window.status = "Comte rebour fini";
}

tRebour=setTimeout ("Rebour();", 1000);
}
Rebour();
</script>

<?php echo $data ?>

qu'est ce que ca t'affiche dans ta source ?

var date2 = new Date ("<?php echo ($data); ?>");