Conversion tracking and passing sale amount

I have a page called ordercompletion.php, which will house the conversion tracking code for Adwords.

A variable called amount is passed to this page.

e.g. mysite.com/ordercompletion.php?amount=50

Since the amount will change from time to time, how would I pass on this dynamically generated amount to the Adwords tracking code?

Below is the code they have for a hardcoded value. But I want dynamic values.

<!-- Google Code for Purchase Conversion Page --> 
<script language="JavaScript" type="text/javascript"> 
<!-- 
var google_conversion_id = 1234567890; 
var google_conversion_language = "en_UK"; 
var google_conversion_format = "1"; 
var google_conversion_color = "666666"; 
if (5.0) { 
Google AdWords Conversion Tracking Setup Guide 
4

  var google_conversion_value = 5.0; 
} 
var google_conversion_label = "Purchase"; 
//--> 
</script> 
<script language="JavaScript" src="http://www.googleadservices.co.uk/pagead/conversion.js"> 
</script> 
<noscript> 
<img height=1 width=1 border=0 
src="http://www.googleadservices.co.uk/pagead/conversion/1234567890/?value=5.0&label=Purc
hase&script=0"> 
</noscript> 

Code (markup):

Any ideas?

Thanks,

Jon

 

"Conversion tracking works with most of the popular webpage development languages available. For example, ASP users most likely have a dynamic variable such as <%=totalValue%>, while sites built with PHP resemble <?echo $totalValue?>."


Source

There is also a PDF: https://adwords.google.com/select/setup.pdf

A little tip here, pass your PROFIT value rather than total value. It will allow easier ROI tracking and spend tracking in AdWords.