/*Javascript*/
var d=new Date();
var offset = d.getTimezoneOffset()*60;
var timestamp = Math.ceil(d / 1000); //give this to PHP
console.log('offset:'+offset);
console.log('timestamp:'+timestamp);
console.log(d.show());
/*PHP*/
$offsetServer= date_offset_get(new DateTime); //in hour
echo "Offset server : "; echo $offsetServer; echo "n";
$today = new DateTime("now");
echo "Current date server : "; echo date('Y/m/d H:i:s', $today->getTimestamp()); echo "n";
$ts=1392381052; //in minute - get by javascript
$offsetClient=18000; //in seconde - get by javascript
$offset=$offsetClient+$offsetServer; //in second
$modifiedServer=$today;
$modifiedServer=$modifiedServer->setTimestamp($ts);
echo "Modified date server : "; echo date('Y/m/d H:i:s', $modifiedServer->getTimestamp()); echo "n";
$modifiedClient=$today;
$modifiedClient->setTimestamp($ts-$offset);
echo "Modified date client : "; echo date('Y/m/d H:i:s', $modifiedClient->getTimestamp()); echo "n";