using jquery getScript to load js file

In index.html I load p5:

and use jQuery to load another page on a button click:

<script>
    $(document).ready(function(){
        $("#btn").click(function(){
            $("#contentx").load("content1.html");
        });
    });
</script>

and it works fine. In content1.html I have (among other things):

<script>
    var url = "drawfarm.js";
    $.getScript(url);
</script>

to load a script containing the p5 content and I get an error:

"p5.min.js:3 Uncaught (in promise) TypeError: Cannot read properties of null (reading 'appendChild')"

Can someone explain what's going wrong?