The usage and related functions of generating random Numbers in JS

First, I will introduce some functions related to random Numbers:
var Rand = Math.random();

1.Math.random(); The result is 1 random number between 0 and 1 (including 0, excluding 1). 2.Math.floor(num); The parameter num is 1 value, and the result of the function is the integer part of num. 3.Math.round(num); The parameter num is 1 value, and the function result is the integer after num4 is rounded into 5.

Math: Mathematical object that provides mathematical calculations of data.
Math.random(); Returns 1 random number between 0 and 1 (including 0, not including 1).

Math.ceil(n); Returns the smallest integer greater than or equal to n.
Use Math. ceil (Math random (10); , mainly getting random integers from 1 to 10, with a very small chance of getting 0.

Math.round(n); Returns the value of an integer rounded off from n4.
Use Math. round (Math random ()); Random integers from 0 to 1 can be equalized.
Use Math. round (Math random (10); , the random integer from 0 to 10 can be obtained by basic equilibrium, and the probability of obtaining the minimum value of 0 and the maximum value of 10 is less than 1 half.

Math.floor(n); Returns the largest integer less than or equal to n.
Use Math. floor (Math random (10); , a random integer from 0 to 9 can be equalized.
Random sweepstakes are also extensible, such as setting the probability of sweepstakes, and using database 1.

// The probability of winning, 100% Winning the lottery, 3 Item prize, but the probability of getting a book is zero 20%
function draw() {
  var d_s = GetRandom(100);
  if (d_s >= 1 && d_s <= 40) {
    alert(' Congratulations on your drawing XXX ! ');
  } else if (d_s >= 41 && d_s <= 80) {
    alert(' Congratulations on your drawing XXX ! ');
  } else {
    alert(' Congratulations on getting the book! ');
  }
}

Corresponding function code of js to generate random Numbers:

<script> 
 2function GetRandomNum(Min,Max)
{  
  var Range = Max - Min;  
  var Rand = Math.random();  
  return(Min + Math.round(Rand * Range));  
}  
 8var num = GetRandomNum(1,10);  
 9alert(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;
}

Above is the detailed content of this article, hope to be helpful to your study.