# JS generates random numbers in a specific range [four situations], and js random numbers

Source: Internet
Author: User

JS generates random numbers in a specific range [four situations], and js random numbers

Preface:

JS does not have ready-made functions and can directly generate random numbers within a specified range.

However, it has a function: Math. random (), which can generate a random number of [0, 1.

With this, we can generate a random number within the specified range.

If the range is involved, there is a boundary value problem. In this way, there are four situations:

1) min ≤ r ≤ max (this is common)

2) min ≤ r <max

3) min <r ≤ max

4) min <r <max

1. min ≤ r ≤ max

`Function RandomNumBoth (Min, Max) {var Range = Max-Min; var Rand = Math. random (); var num = Min + Math. round (Rand * Range); // rounding return num ;}`

2. min ≤ r <max

`Function RandomNum (Min, Max) {var Range = Max-Min; var Rand = Math. random (); var num = Min + Math. floor (Rand * Range); // return num ;}`

3. min <r ≤ max

`function RandomNum(Min, Max) {      var Range = Max - Min;      var Rand = Math.random();      if(Math.round(Rand * Range)==0){               return Min + 1;      }      var num = Min + Math.round(Rand * Range);      return num;}`

Iv. min <r <max

`function RandomNum(Min, Max) {      var Range = Max - Min;      var Rand = Math.random();      if(Math.round(Rand * Range)==0){        return Min + 1;      }else if(Math.round(Rand * Max)==Max)      {        index++;        return Max - 1;      }else{        var num = Min + Math.round(Rand * Range) - 1;        return num;      } }`

The above JS generates a random number in a certain range [four situations] is all the content shared by Alibaba Cloud. I hope you can give us a reference and support for the customer's house.

Related Keywords:
Related Article

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

## A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

• #### Sales Support

1 on 1 presale consultation

• #### After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

• Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.