@TAdeleye_WMF my suggestion would be:
if the css class client-js is present, we enable drag and drop for STV and if it is not present, or client-nojs is set, the previous interface with the dropdowns is used. I would not use any other alternative such as multiselect, as the order can also play a role here, so I would leave it as it is.

@jsn.sherman from what I was told, it should allow getting html and wikitext result, because the current state is that getTextResult returns also an html string but should be wikitext. If I run the tally.php it will be wikitext and if I add --html i will get html string and this should be everything for this task. That's what I know about it

Yes - I used minimum value "0" and maximum value "1" because if you create the range "-1" to "1" it will add "0". Also if you select "-5" and "5" it will add all integers in between, including "0".
I tested what happens if you don't vote anything: For the ballot with "0" and "1" it was tallied with "0". I also checked this with a ballot including numbers "1" and "2" - then its not possible to submit a blank vote, so blank is always counted with "0" in this case.

If I understand this correctly: this is about having the option to create a histogram range ballot with no default value selected when someone wants to vote.