assume that there is a a.php facet
with the introduction of abc.js and a abc.min.js ( abc.js core), which is the package needed for this facet. There is no problem with this.

<script src="abc.min.js"></script>
<script src="abc.js"></script>
</body>

but
when I use require_once to introduce a b.php file in a.php ,
b.php is also useful for this suite. When I use ajax GET to retrieve the data of b.php and return to a.php, which suite becomes unusable?

<div id="tab"></div>

$(".btn").click(function(e) {
  e.preventDefault();
  var id = e.currentTarget.dataset.id;

  $("-sharptab").html("...");

  $.ajax({
    type: "GET",
    url: "b.php?id="+id,
    success: function(data){
      $("-sharptab").html(data);
    }
  });

});

but obviously it can be used in a.php .

so I wonder: I need to introduce abc.js again in a.php print b.php ?
so I put < script src= "abc.js" > < / script > after b.php , it works!
but what matters is that my two JS abc.min.js and abc.js introduce
under < div id= "tab" > < / div > like this:

<div id="tab"></div>

<script src="abc.min.js"></script>
<script src="abc.js"></script>

so when I introduced b.php into tab (because I also added < script src= "abc.js" > < / script > to b.php )
problem is that this JS must be executed abc.min.js before it can be used, but it can be used when abc.min.js has not been fetched?
but there is a reporting error: XXX not defind

Why did this happen?
how can I improve this?