$( document ).ready(function() {
if (pll_current_language() == 'en') {
?>
$('.logo').css("background-image", "url(images/logo.png)");
} else if (pll_current_language() == 'zh') {
?>
$('.logo').css("background-image", "url(images/logo-CN.png)");
} else {
?>
$('.logo').css("background-image", "url(images/logo.png)");
}
?>
});