index.html

<doctype html>
<meta charset="UTF-8">	
<title>See what Hacker News looked like on the day you joined</title>
<style>
	@keyframes flubber {
	    from {padding:30px;}
	    to {padding:50px;}
	}

	#誤 { 
		background: yellow;		
	}
	body {
		background: #F6F6EF;
		font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif;
		font-weight: 300;
		line-height: 21px;

		display: flex;
		align-items: center;
		justify-content: center;
	}
	input {
		border-radius: 5px;
		font-size: 150%;
		padding: 10px 20px;
	}
	h1, input {
		margin: 5px 5px 5px 0px;
	}
	form {
		max-width: 900px;
		margin: 0 auto;

		padding: 50px;
		border: solid 1px white;
		border-radius: 3px;
		background: white;
		box-shadow: 0px 0px 4px rgba(0,0,0,0.2);

		animation-name: flubber;
		animation-duration: 1s;
		animation-timing-function: cubic-bezier(0,4.5,0.5,1);
	}
	h1 {
		padding: 0px 0px 31.4159265358979px 0px;
		font-size: 30px;
		font-weight: 300;
	}
	#postamble {
		margin-top: 50px;
	}
	img {
		display: none;
	}
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="https://cdn.firebase.com/js/client/2.2.7/firebase.js"></script>
<form>
	<img src="bf.gif">
	<div id=allelse>
		<h1>See what Hacker News looked like on the day you joined</h1>
		<input type=text autofocus placeholder="HN username" name=username id=username>
		<input type=submit>
		<p><span id=誤>
			Sorry, your username was not found. Maybe you have never submitted or commented
			anything? Note that the username is case sensitive.
		</span></p>
		<div id=postamble>
			<p>Inspired by <a href="http://i.puthtml.com/revgeorge/cakeday">a similar tool for Reddit</a></p>
			<pre>
Changelog:
2018-02-28  Updated to use /front?day=... instead of archive.org
2015-07-19  Created</pre>
		</div>
	</div>
</form>

<script>
$(function () {
	var 火 = new Firebase("https://hacker-news.firebaseio.com/");
	$("#誤").hide();
	$("form").submit(function () {
		火.child("v0/user/" + $("#username").val()).on("value", function(結果) { 
			var 人 = 結果.val();
			if (人 && 人.created) {
				var 時 = new Date(人.created * 1e3);
				var ꜛ = "https://news.ycombinator.com/front?day=" + 時.toISOString().slice(0,10);
				$('#allelse').hide();
				$('img').show();
				location = ꜛ;
			} else {
				$("#誤").show();
			}
		});
		return false;
	});
});
</script>