[Dilettante_Pro]

<div id="pjax-container"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
var x = '<div><div></div><div id="pjax-container">Target</div></div>';
var data = $(x);
alert(data.is("#pjax-container"));
if (data.find("#pjax-container")) {
    var container = data.find("#pjax-container");
    $("#pjax-container").html(container.html());
}

</script>