What is the Save and Scooby Doo Technique?

Nice Dan,  I need a flavor of this... I need to fire some more javascript after we have the RID.  I am not sure how to modify the sccobyDoo to do that?  I tried placing a  function call but it doesn't work... I am sure because I don't quite understand how you are making the new page appear?  Can you help with how to get the next function to run?

Thanks, Dean  
Here is what I tried...
(function(){
  var querystring=document.location.search;

  if (/nwr/i.test(querystring)) {

    $("<iframe>", {id: "QBU_editform", name: "QBU_editform"})
      .css({display: "none"})
      .appendTo("body")
      .on("load", function() {
        QBbusyHide();
        var rid = this.contentWindow.kRid;

   


       var markup = "";
        markup += "<h2>You just created a new record with [Record ID#] = " + rid + " !<h2>";
        markup += "<center><img src=&#039;http://vignette3.wikia.nocookie.net/hanna-barbera/images/2/24/Scoobydoo.jpg' height='200'></center>";
        $("<div>").html(markup).dialog({
           title: "Save and Scooby Doo!",
          modal: true,
          close: function(event, ui) {
               testAlert(rid);
            document.location.href = gReqDBID + "?a=er&rid=" + rid;
          }
        });
      });
    $("form[name=editform]").prop({target: "QBU_editform"});
  }
})();

function testAlert(rid) {

   alert("in testAlert... so I can start and do whatever I need to now that I have the new record id of "+rid);

}