Uncaught SyntaxError: Unexpected identifier within bookmarklet

I am trying to inject jquery into a page for use in a bookmarklet. I'm having some trouble with the syntax of the callback as I am getting the following error when I run it:

Uncaught SyntaxError: Unexpected identifier

The code is below. The error shown in the console looks like its happening near where I call the createScript function. Its a little hard to tell because the code is all smushed. When I paste into JSLint it shows this message:

Expected ';' and instead saw 'createScript'.

Code:

(function() {  
  console.log("Starting....");
  var createScript = function (url,callback) {
    /* Insert Datatables */                  
    var script_set = document.createElement("script");
    script_set.setAttribute("src", url);
    script_set.addEventListener("load", callback);
    document.body.appendChild(script_set);
  }
  
  createScript("https://code.jquery.com/jquery-3.6.0.min.js", function () {
    console.log("jquery loaded....");
  });
}
)();

UPDATE

I got it working by making the following change to the top. Just not sure why the error.

Working code:

(function() {
  console.log("Starting....");

  function createScript(url, callback) {
      var script = document.createElement('script');
      script.type = 'text/javascript';
      script.src = url;
      script.async = false;
      script.onload = callback;
      document.head.appendChild(script);
  }
  
  createScript("https://code.jquery.com/jquery-3.6.0.min.js", function () {
    console.log("jquery loaded....");
    console.log("jquery version = "+ $().jquery);
  }
              );
}
)();

If anyone knows why I got an error with the top code I would appreciate it to better my understanding of JavaScript.