Question

Where is the JS file and is this Async the fastest way to call JS?

I guess they then have PHP calls in the .JS for updating the Ad stats??

The code:

<script type="text/javascript">
(function(){ 
     var acc = "acc_230d269_pub";
     var st = "nocss";
     var or = "h";
     var e = document.getElementsByTagName("script")[0];
     var d = document.createElement("script");
     d.src = ('https:' == document.location.protocol ?'https://' : 'http://')+"engine.influads.com/show/"+or+"/"+st+"/"+acc;
     d.type = "text/javascript"; 
     d.async = true;
     d.defer = true;
     e.parentNode.insertBefore(d,e);
 })();
 </script>

Answer 1

I’ve made your code more readable:

1 <script type="text/javascript">
2 (function () {
3   var acc = "acc_230d269_pub";
4   var st = "nocss";
5   var or = "h";
6   var e = document.getElementsByTagName("script")[0];
7   var d = document.createElement("script");
8   d.src = ('https:' == document.location.protocol ? 'https://' : 'http://') +
9                "engine.influads.com/show/" + or + "/" + st + "/" + acc;
10  d.type = "text/javascript";
11  d.async = true;
12  d.defer = true;
13  e.parentNode.insertBefore(d, e);
14 })();
15 </script>

• 2,14 An anonymous function wrapper is created, so that variables cannot be access from outside the function (“scope”)
• 3   acc looks like the identifier of the advertiser
• 4,5 st = "nocss" and or = "h" looks like settings to adjust the appearance
• 7,10-12 A <script> tag is created. async = Loading the script will not block the execution of the document. defer=true prevents the script from not being executed (can be omitted)
• 6,13 The newly created script tag is inserted before (13) the first script tag in the document (6,13)
• 8,9 The URL is constructed:
  If the current page is transmitted over a secure connection, the injected script will also be transferred over the HTTPS protocol.

The extension of the requested file is omitted. This file could be served using the application/javascript MIME type by server configuration.