Random number between -10 and 10 in JavaScript

Question

Possible Duplicate:
Generating random numbers in Javascript

How do I get a random number between −10 and 10 in JavaScript?

Answer 1

Using not more than a simple Google search,

var randomnumber=Math.floor(Math.random()*21)-10

Math.random()*21)returns a number between 0 and 20. Substracting 10 would yield a random number between -10 and 10.

My advice: try to Google first, and than ask about the results, e.g.:

What is the best way to get a random number? I've googled and found methods X and Y, and wondered which is best for purpose Z.

Answer 2

var min = -10;
var max = 10;
// and the formula is:
var random = Math.floor(Math.random() * (max - min + 1)) + min;

Answer 3

jQuery: $.randomBetween(minValue, maxValue);

Answer 4

For example:

var min = -10;
var max = 10;
Math.floor(Math.random() * (max - min + 1) + min)

see http://thepenry.net/jsrandom.php for some comparaison of Math.floor, Math.ceil and Math.round