D2L catch LTI as parameters from a URL

Question

I'm trying to send the orgUnitId of a course from a widget in D2L to a webpage (stored on the same server). The webpage is displayed in the widget via an <iframe>.

Example:

<iframe src="http://valence.newbie.edu/d2l/custom-widget/?orgunitcode={OrgUnitCode}&amp;"></iframe>

How can I catch the orgunitcode from the URL (like a parameter in a script stored on the server)?

Thanks in advance