::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact

Mark New Comments

August 31st, 2014
tech, comments  [html]
Online discussion spaces tend to use either linear or threaded comments. With linear comments there's just one long series of responses while with threads each comment is attached to the one it's replying to. In general I really like threads: the clarity they give you is very powerful, allowing a large number of people to have a coherent discussion by all breaking off into their own overlapping mini-discussions around individual posts. A downside to threads, however, is it's very hard to come back to a discussion and see what's changed. If you just have a linear discussion you find the last comment you remember and read from there, but with threads you're kind of lost.

One solution is for the page to keep track of when you last visited, and highlight any comments that have been posted since then. I first saw this on lesswrong, more recently it's been added to slate star codex, and now I've added it to the comments here:

See how there's a little black line to the left of Alex's comment? That means it was posted more recently than the last time I visited the page.

Warning: boring technical details follow.

While you could do this sort of thing with local storage, I wanted this to work on as many browsers as possible, so I used cookies. The key bit of javascript is this:

var last_visit = document.cookie.replace(
   /(?:(?:^|.*;\s*)jtk_last_visit\s*\=\s*([^;]*).*$)|^.*$/, "$1");
var current_time = new Date().getTime();
var one_year_gmt_str =
   new Date(current_time + 31536000000).toGMTString();
document.cookie = "jtk_last_visit=" + current_time +
                          "; path=" + window.location.pathname +
                       "; expires=" + one_year_gmt_str;
What does this do? The first line reads the cookie jtk_last_visit if the browser sent it. If no value was sent it will just be "". (The crazy regex comes from an MDN post.) The next three lines set the jtk_last_visit cookie to the current time, make it expire one year later, and restrict the path to be for this page only. That's important: otherwise visiting any page on the site would clear your highlighted comments.

Now you have some javascript that does:

var comment_is_new = last_visit.length > 0 &&
                     comment_epoch_ts > last_visit/1000;
And you mark up the comments based on comment_is_new.

Comment via: google plus, facebook

Recent posts on blogs I like:

Assume Nordic Costs: London Edition

A month ago I made maps proposing some subway and regional rail extensions in New York and noting what they would cost if New York could build as cheaply as the Scandinavian capitals. Here is the same concept, but with London rather than New York. Here is…

via Pedestrian Observations June 25, 2019

Instead of “I’m anxious,” try “I feel threatened”

cw: teaching to learn I have a long history with anxiety, and I’m pretty good at noticing when it’s happening. The problem is that I’m always anxious. Noticing anxiety doesn’t snap me out of anxiety– in fact, it often produces meta-anxiety, anxiety about …

via Holly Elmore June 20, 2019

Checkmate on blackmail?

It has been argued that blackmail should be legal if gossip is legal, and even that there are no good consequentialist counterarguments (!). I think this isn’t obvious because the disclosures incentivized by blackmail are systematically worse than gossip.…

via The sideways view June 2, 2019

more     (via openring)

More Posts:


  ::  Posts  ::  RSS  ::  ◂◂RSS  ::  Contact