Pass URL to iframe in WordPress

I have a wordpress site with an iframe that displays custom content from an external site.

Here is my iframe:

<iframe src="https://www.targetsite.com/UNIQUECODE" width="800" height="800"> 

I want the "UNIQUECODE" in the iframe to populate based on the browser URL (my site is example.com):

http://www.example.com/iframepage?UNIQUECODE 

Is this possible in wordpress?