You write one "electronic sheet of paper" and put it on a computer that is always on and reachable from anywhere. Anyone who opens the link gets an identical copy.
That's really it. Everything else is detail.
2
How is it different from a group-chat sign-up?
BEFORE
Someone posts a list, and everyone copies the last message and adds their name
One bad copy-paste and the whole list is wrecked. Who's bringing a partner, who can't eat spicy food? Scroll up and find out. And you have to count heads yourself.
NOW
Share one link, everyone fills in their own line, and the list builds itself
The count adds up automatically, food notes sit right after each name, changing your mind takes one tap, and nobody can overwrite anybody.
In plain words: before, everyone took turns keeping the books. Now someone who never gets tired and never makes a mistake keeps them for everybody.
3
Three things make the page
Think of building a house: first the walls, then the paint, then the light switches. A web page works the same way, one thing per step.
First, walls
HTML
Put the content where it belongs: title on top, date in one block, names in a row, button right here. Like a bare concrete shell: you can tell where the door and windows are, but it's dull and gray.
Then, paint
CSS
Pick the colors, the text size, how round the corners are, how much empty space to leave. Same walls, now they look decent. All the "pretty" you see comes from this layer.
Last, switches
JavaScript
Make it do things: tap "I'm in" and a form pops up, finish it and a new row appears on the spot, and every 20 seconds it checks for new sign-ups by itself. Without this layer, it's just dead paper.
All three are plain text files. You could write them in Notepad. Really, there's no magic.
4
But where do the names go?
Everyone gets their own copy of the page, but the names people fill in have to land in one shared notebook. Otherwise you couldn't see mine. So there are two more players.
① Front deskThe page you see on your phone. It looks nice and collects what you type.
② Back-room notebookEvery name goes into this one notebook, kept in someone else's server room, not on your phone or mine.
③ Running back and forthYou tap confirm and the front desk carries your name to the notebook. When someone else opens the page, it copies the whole notebook out for them.
This "front desk + notebook" is rented, for almost nothing, and for a small crowd it costs not a cent. No need to buy a computer and keep it at home.
5
How the street address gets set up
Once everything is in place, people have to be able to find it. seafood.shangfei.shop is the street address. We own the plot called shangfei.shop and can open as many doors on it as we like. Today we opened one called "seafood".
Setting up an address is just adding one line to a worldwide phone book: whenever someone types this name, send them to our machine. It takes effect in seconds.
So if you want another one tomorrow, say "Hot Pot Next Week", you can hang a new address in ten minutes, and the two never interfere.
6
Going live takes one sentence
"Push" what you wrote upType one command and within seconds everyone in the world sees the new version. Made a mistake? Type one more and you're back on the previous version.
This very page went from nothing to something you could open in under twenty minutes.
7
What this page actually does
States time and placeTonight at 6 · the hall at Zhiyuan (our restaurant)
Collects namesAnd how many people you're bringing
Counts headsHow many more to fill the table
Notes food wishesNo spice, extra mantis shrimp
Lets you change your mindOne tap to switch to "can't come"
Refreshes itselfYou see new sign-ups as they happen
8
Two things it skips on purpose
No login, no phone numberJust type a name. It doesn't know who you are and doesn't want to. It's a get-together among friends, and adding a gate would just mean nobody fills it in.
The other one: everybody can see the list. That's on purpose. A sign-up should be visible to all, or someone will have to ask "so how many are coming?"
"So I could make one too?"
Yes. The hard part was never the writing. It's deciding what belongs on the page and what doesn't. What really took time on this page was deciding that "just a name" is enough.
