A summary of the methods of generating random numbers by JS [Favorites]

A summary of the methods of generating random numbers by JS

JS generates random numbers primarily using the random () method of the built-in math object. Usage such as: Math.random (). It returns a random number between 0 and 1. With such a method, it is understandable to generate arbitrary random numbers. For example, in practice we may have the following needs:

(1) generate a random integer between 0-100, then you can:

1. parseint (100*math.random ());

Note: Because the return value of Math.random () is 0 and 1, there is the possibility of generating 0 and 100.

(2) generate a random integer from M-n, for example to generate a random number between 5-15, you can:

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

The summary is:

parseint (Math.random () * (n-m+1) +m);//Generate a random integer from M-n

In addition, according to the need www.phpernote.com summed up the other two commonly used methods, as follows:

(1) generating a random integer of the specified number of digits

1. function Randomnum (n) {
2. var t=';
3. For (var i=0;i<n;i++) {
4. T+=math.floor (Math.random () *10);
5. }
6. return t;
7. }

(2) Generate random integers in the specified range

2. function Randomnum (minnum,maxnum) {
4. switch (arguments.length) {
6. Case 1:
8. return parseint (Math.random () *minnum+1);
10. Break ;
12. Case 2:
14. return parseint (Math.random () * (maxnum-minnum+1) +minnum);
16. Break ;
18. Default:
20. return 0;
22. Break ;
24. }
26. }

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

This article original address: http://www.daimajiayuan.com/sitejs-17200-1.html

A summary of the methods of generating random numbers by JS [Favorites]