Don’t post them on dart or anywhere online. You open yourself up to a whole host of legal related issues, and it’s a pretty good chance it will never go anywhere - even if what you write is awesome.
If it’s a weird or esoteric comedy, you have to be an exceptionally good writer for it to go anywhere and more work than you can fathom unless you ligerally luck out with open submission. If it’s a middle of the road fox comedy, or Nickelodeon canned laughter and it’s kinda funny - it may help you as part of a portfolio to get a job writing - but that’s still hard.
My knowledge is more novel related, but I’ve written a few scripts before - years back - they’re easier to write than novels, but much harder to sell to an agent or a production house - and you’re much more likely to be using them to get a job writing for another show. But I will tell you now, the process of writing, and laughing to yourself reading your own work is the only fun part about it - and as an exercise in time wasting - it’s totally worth doing.