使AJAX通话更安全

I did this script for a project of mine, but I would like to void users to inspect elements and change some values here, like ID and page to redirect. There is a way to do it without make lots of protection in server side?

window.setInterval(function(){
var dataString = 'id='+<?=$userDetails->id;?>;
$.ajax({
    type:'POST',
    data:dataString,
    url: 'game2.php',
    success:function(data) {
    }
});
}, 6000);

Thank you!