Js randomly generates random animated numbers and js letters in a combination of letters and numbers.

Js randomly generates random animated numbers and js letters in a combination of letters and numbers.

Js random animation generates a set of random numbers

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Effect description:

Only one index.html file in the attachment is valid.

It contains css and html.

Random numbers generated by pure js

Do not repeat each time. click the button and switch again.

Usage:

1. Introduce css styles into your webpage

2. Copy the code in the body to the desired part.

JS generates a random string composed of letters and numbers

 Preface

A recent requirement is to generate a random string of 3-32 characters in combination with letters and numbers, and a 43-bit random string.

Method 1

Fantastic writing

Math.random().toString(36).substr(2);

Output result

Explanation

It is very interesting. After studying it, basically the parameter after toString can be any integer between 2 and 36. If not written, the default value is 10 (that is, decimal). At this time, the returned value is the random number.

If it is an even number, the returned value string is short. If it is an odd number, the returned value is a very long value.
If the value is less than 10, it is composed of digits. If the value is greater than 10, it contains letters.
Therefore, if you want to get a long string of random characters, you need to use a parameter greater than 10 and an odd number. In addition, you can use slice (2, n) to intercept the string based on the length!

Method 2

There are a lot of implementation methods, because the previous method does not meet the requirements, so I wrote the next one, welcome to shoot bricks.

Address

Https://gist.github.com/xuanfeng/b23ab28ab412254e1594

Code

/*** RandomWord generates a random combination of letters, numbers, and numbers of any length ** randomFlag-length min-bit [fixed-digit] max-length max-bit ** xuanfeng * /function randomWord (randomFlag, min, max) {var str = "", range = min, arr = ['0', '1', '2', '3', '4 ', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E ', 'F', 'G', 'h', 'I', 'J', 'k', 'l', 'M', 'n', 'O ', 'P', 'Q', 'R','s ', 't', 'U', 'V', 'w', 'x', 'y ', 'Z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'h', 'I ', 'J', 'k', 'l', 'M', 'n', 'O', 'P', 'Q', 'R','s ', 'T', 'U', 'V', 'w', 'x', 'y', 'z']; // random if (randomFlag) {range = Math. round (Math. random () * (max-min) + min;} for (var I = 0; I <range; I ++) {pos = Math. round (Math. random () * (arr. length-1); str + = arr [pos];} return str ;}

Usage

Generate 3-32 random strings: randomWord (true, 3, 32)

Generate 43 random strings: randomWord (false, 43)

Usage of random numbers generated by js

<script> function GetRandomNum(Min,Max){ var Range = Max - Min; var Rand = Math.random(); return(Min + Math.round(Rand * Range)); } var num = GetRandomNum(1,10); alert(num); </script>var chars = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];function generateMixed(n) { var res = ""; for(var i = 0; i < n ; i ++) {  var id = Math.ceil(Math.random()*35);  res += chars[id]; } return res;}

1. Math. random (); the result is a random number (including 0, not 1) between 0 and 1)

2. Math. floor (num); The num parameter is a numerical value, and the function result is an integer part of num.

3. Math. round (num); The num parameter is a numerical value, and the function result is an integer rounded to num.

Math: A mathematical object that provides mathematical computation of data.

Math. random (); returns a random number between 0 and 1 (including 0, excluding 1.

Math. ceil (n); returns the smallest integer greater than or equal to n.

When Math. ceil (Math. random () * 10) is used, a random integer ranging from 1 to 10 is obtained. The probability of a random integer from 0 is very small.

Math. round (n); returns the integer value after n rounding.

Use Math. round (Math. random (); a random integer ranging from 0 to 1 can be obtained evenly.

When Math. round (Math. random () * 10) is used, a random integer ranging from 0 to 10 can be obtained in a balanced manner. The probability of obtaining the minimum value 0 and the maximum value 10 is less than half.

Math. floor (n); returns the largest integer less than or equal to n.

When Math. floor (Math. random () * 10) is used, a random integer ranging from 0 to 9 can be obtained evenly.

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