Yes, but it's a constant source of frustration.
It's a two-step process, and requires constant tweaking. I have a browser plug-in that saves the page as you see it (using the DOM). I also have a plug-in that enters my passwords. Then I drive the browser with a scripting scheme that uses image matching, which gets me to the holdings screen, at which point I save the page. The second step is a program that parses the HTML files saved above and makes a single CSV file that has all positions across all investment and banking sites. It's a hobby.