Example of js method for generating random numbers and js random number instances

Example of js method for generating random numbers and js random number instances

Js generates random numbers mainly using the random () method of the built-in Math object. Usage example: Math. random (). It returns a 0 ~ A random number between 1. With this method, it is easy to understand how to generate any random number. For example, we may have the following requirements:
(1) generate a random integer between 0 and 100, then you can:

parseInt(100*Math.random()); 

Note: because the return values of Math. random () include 0 and 1, it is possible to generate 0 and 100.
(2) generate a random integer between m-n. For example, to generate a random number between 5-15, you can:

parseInt(Math.random()*(15-5+1) + 5); 

In general, it is:

ParseInt (Math. random () * (n-m + 1) + m); // generates a random integer between m-n.

In addition, the following two common methods are summarized as needed:
(3) generate a random integer with the specified number of digits

function randomNum(n){  var t='';  for(var i=0;i<n;i++){  t+=Math.floor(Math.random()*10);  }  return t; } 

(4) generate a random integer in the specified range

function randomNum(minNum,maxNum){  switch(arguments.length){  case 1:   return parseInt(Math.random()*minNum+1);  break;  case 2:   return parseInt(Math.random()*(maxNum-minNum+1)+minNum);  break;  default:   return 0;  break;  } } 

For example, to generate a random integer between 2-9, then: randomNum (), generate a random integer between 1-22, then: randomNum (22)

The above is the method used to generate random numbers in summary js. I hope it will be helpful for your learning.