How to create a tracking script with js and php?

What I can't figure yet is what are the ways to do this? Google from what I see is loading a gif file, stores the information and parses the logs. If I do something similar sending the data to a php file Ajax cross site policy will stop me开发者_如何学编程, from what I remember.

So what is a clean way to do this ? ( I don't need code just the logic behind it )

Method a - web bug:

Give the user this:
<img src="http://www.yourserver.com/yourtracking.php?associateid=3rdpartyid" width="1" height="1" />

have the php return header("content-type:image/gif"); and serve them a gif file for their effort.

Method b - script

Create a php file that can parse parameters and have it return content-type:text/javascript Have them load it like this: <script type="text/javascript" src="http://www.yourserver.com/yourtracking.php?associateid=3rdpartyid"></script>

If you want to you can do additional stuff like

<script type="text/javascript">
  var associateId = "12345";
  var trackingPage="homepage";
</script>
<script type="text/javascript" src="http://www.yourserver.com/yourtracking.php?associateid=3rdpartyid"></script>

then in the php have code like this (watch the nested quotes)

$str = 'var url = "http://www.yourserver.com/moretracking.php?associateid="+associateId+';
$str .= '"&page="+trackingPage+"&ref="+escape(document.referrer);\n';
$str .= 'document.write(\'<img src="\'+url+\'"/>\');';

echo $str;

You may read this (found googling) about cross domain ajax and its possible solutions... http://snook.ca/archives/javascript/cross_domain_aj/

Well, i use some php code that is included in my script that logs Ip Addresses and as much information i can get from a server-side perspective. It saves it in a MySql Database. I also use a Ajax script to post data to a php script, the data in this case is Screen Heigth and thing you only can get client-side.