Reddit New Comment Highlighting

A free Gold feature

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Reddit New Comment Highlighting
// @description  A free Gold feature
// @version      1.0.0
// @namespace    skeeto
// @license      Public Domain
// @include      http*://*.reddit.com/*
// @grant        none
// ==/UserScript==

var HLN = HLN || {};

HLN.highlight = function(cutoff) {
    $('.entry').each(function() {
        var date = new Date($(this).find('time').attr('datetime')).getTime();
        if (date > cutoff) {
            $(this).addClass('new-comment');
        } else {
            $(this).removeClass('new-comment');
        }
    });
};

HLN.subreddit = function() {
    var match = /\/comments\/([a-z0-9]{6,})/.exec(window.location);
    return match != null ? match[1] : null;
};

HLN.lastvisit = function() {
    var subreddit = HLN.subreddit();
    if (subreddit != null) {
        var last = window.localStorage[subreddit + '-lastvisit'];
        if (last != null) {
            return parseFloat(last);
        } else {
            return null;
        }
    } else {
        return null;
    }
};

HLN.mark = function(time) {
    var subreddit = HLN.subreddit();
    if (subreddit != null) {
        return window.localStorage[subreddit + '-lastvisit']
            = time || Date.now();
    } else {
        return null;
    }
};

HLN.run = function() {
    var last = HLN.lastvisit();
    if (last) {
        HLN.highlight(last);
    }
    HLN.mark();
};

HLN.run();