Pick for us: a name, who goes first, teams, a number, a coin, dice

What it can pick

• One name from a list. The list can be up to 200 lines, each up to 60 characters. If you want, the picked name is taken off the list, so the next pick is among those who are left.
• Several names in one pick. No name comes up twice.
• An order for the whole list: who goes first, second, third, to the last.
• Groups or teams, from 2 to 50 of them. They come out the same size, or one name apart when the list does not divide evenly; the first groups get the extra names.
• A number between two numbers, such as a ticket number from 1 to 200. Whole numbers, up to six digits each, and both ends can be picked.
• Heads or tails.
• Dice: 1 to 6 of them, six sides each, with the total.

How it picks

• The chance comes from your browser, from the part of it made for security work (crypto.getRandomValues), 32 bits at a time. The page has no formula of its own for it, and it does not use the clock.
• No place on the list is more likely than another. The browser gives one of 4,294,967,296 numbers, and that count seldom divides evenly by the length of a list. So the few numbers left over at the top are thrown away and another is asked for; what is left divides evenly.
• An order is made by swapping. From the last place to the second, each place is swapped with a place picked from itself and those before it. Several names are the first few of such an order; groups are such an order dealt out one name to each group in turn.
• A name written on two lines is two names. It has two chances, and in an order or in groups it appears twice.
• Each die is its own pick, and so is each press of the button. The page does not look at what came up before.
• Nothing moves on the screen. No wheel turns and no coin spins: the answer is shown at once, and a screen reader is told it.

So that everybody can see

• Every pick has a number, counted from when the page was opened: Pick 1, Pick 2, Pick 3. If the button was pressed until a wanted name came up, the count shows it.
• Every pick since the page was opened is listed at the bottom, newest first, up to the last 30. The list is gone when the page is closed or loaded again.
• Agree first, then press. Say out loud what is being picked and that this pick is the one that counts, before anybody knows the answer.
• Let the others see the list before the pick: every name on it, and no name twice unless that was agreed.
• One person can press and another can read it out. The page does not care who holds the phone.

What this page does not do

• It cannot show anybody afterwards that a pick was made by chance. A screen can be loaded again and a list can be changed. The people it matters to have to be there and watch, or trust the one who pressed.
• It knows no rule about raffles, lotteries, prize draws or contests. Such rules differ from place to place, and this page has read none of them.
• It did not make your browser’s source of chance and cannot test it on your device. It was tried in one browser only (Chromium).
• It does not remember anything. Write the answer down if it has to last.
• It does not make a pick fair by itself. Chance settles something only when the people it touches agreed to leave it to chance, and when each of the answers would be all right. Who gets care, a bed, or a safe place tonight is not a thing for dice.
• It is not for betting, and it has no games. If gambling has become a problem, the guide When gambling is the problem has people to call.

Every time the page is built, a program checks it five ways. It checks 16 examples worked by hand, where the numbers the browser would give are written out in advance. Then, for a small source of 256 numbers and one of 1,000, it tries every number the source could give with every list length up to that many, and checks that each place on the list is reached by exactly the same count of numbers and that the count thrown away is the remainder. It makes up 2,000 picks, and a second reader, written separately, checks that nobody is there twice, nobody is left out, the groups are one name apart at most, and a number is inside its two ends. Last, it counts 1,640,000 picks (names, orders, groups, numbers, coins, dice) and stops the build if any count is further from what an even chance gives than a margin fixed in advance. That count uses a made-up stream of numbers, the same each time, not your browser’s: it tests the recipe, not your device.