Summary of methods for generating random numbers in javascript_javascript skills

<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;
}

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

Math: Mathematical object, providing mathematical calculations on 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 using Math.ceil(Math.random()*10);, you mainly get random integers from 1 to 10, and the probability of getting 0 is very small.

Math.round(n); Returns the value of n after rounding.
Use Math.round(Math.random()); to obtain a random integer from 0 to 1 evenly.
When using Math.round(Math.random()*10);, you can obtain random integers from 0 to 10 in a basically balanced manner, and 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 using Math.floor(Math.random()*10);, random integers from 0 to 9 can be obtained evenly.