Thank you yellow1912 for your response.

I understand that this is a default action of the add link function, but it is a frustrating one for me because I do all my development locally, then upload to a server.
That means I have to edit every link created using HTMLAREA and change it to match the server URL that Zencart has been loaded on. This issue is also experienced when changing domain names.

On the old zencart website there was a HTMLAREA v3 that you could download and install that overcome this issue - there is a HTMLAREA v3 available in the older contributions section, but it is not the copy that solve this problem.

Therefore I need to modify the code that forms the URL so that the inputted URL is the output regardless if it is "relative path" or full path. Can anyone help??

Thanks,