Js random number code Daquan page 1/2

Source: Internet
Author: User

Js random number base
1. javascript random number function Math. random ()

Random (Math. random Method)
Public static random (): Number

Returns a pseudo-random number n, where 0 <=n <1. The returned number is called "pseudo-random" because it is calculated technically in a confidential manner.

Number: a Number.

Generate random numbers within a specified range
The Math. random () method has no parameters. 0 ~ is returned ~ Random number between 1. If 0 ~ is to be generated ~ Random between n
Number, which can be in the following format:

Math. floor (Math. random () * n)
To generate m ~ Random Number between n, which can be used:
Math. floor (Math. random () * n) + m

Javascript random number advanced application
① Since JavaScript was generated, many browsers have built-in random number generation methods. For example:
Var number = Math. random ();
This method generates a floating point number between 0 and 1.
② Based on Time, random numbers can also be generated. For example:
Var now = new Date ();
Var number = now. getSeconds ();
This generates an integer ranging from 0 to 59 based on the current time.
Var now = new Date ();
Var number = now. getSeconds () % 43;
This generates an integer ranging from 0 to 42 based on the current time.
③ Here we will introduce a fairly good random number generator program, which can be applied in many fields.
<Script language = "JavaScript"> <! --
// The Central Randomizer 1.3 (C) 1997 by Paul Houle
// See: http://www.msc.cornell.edu /~ Houle/javascript/randomizer.html
Rnd. today = new Date ();
Rnd. seed = rnd. today. getTime ();
Function rnd (){
Rnd. seed = (rnd. seed * 9301 + 49297) % 233280;
Return rnd. seed/(233280.0 );
Function rand (number ){
Return Math. ceil (rnd () * number );
// End central randomizer. -->
Detailed source reference: http://www.jb51.net/article/12566.htm

So how can we easily obtain a random number within a specified range? After my comparison, My function is the most concise and practical drop on the Internet so far.
Instance code:

[Ctrl + A select all Note: If you need to introduce external Js, You need to refresh it to execute]
Code Description:
Copy codeThe Code is as follows:
// Declare a random number variable. The default value is 1.
Var GetRandomn = 1;
// Obtain the function of the value in the random range
Function GetRandom (n) {GetRandomn = Math. floor (Math. random () * n + 1 )}
// Start the call and obtain a random number ranging from 1.
GetRandom ("100 ");
// View output
Document. write (GetRandomn)

Is the Code quite concise? GetRandomn is the random number variable and can be called at will.
Let's take a random display of the special effect code:
// At the beginning, obtain a random number ranging from 1 to 3.
GetRandom ("3 ");
// Call a project that meets the random number
Switch (GetRandomn ){
Case 1:
Document. write ("when the random number is 1, the script home is displayed ")
Case 2:
Document. write ("www.jb51.net" is displayed when the random number is 2 ")

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