javascript, how to set a var to a certain value then change it randomly

i have this scri开发者_开发百科pt:

var randNum = Math.floor(Math.random() * 3);
if (randNum == 0){
alert ('0');
} else {
alert ('1');
}

and every time it runs i get a random value of 1 or 0

what i want is to always start the randNum var as being 0

any ideas?

thanks

var randNum = null;
function getRand() {
    if (randNum == null){
        return randNum = 0;
    }
    return randNum = Math.round(Math.random());
}

now that will do it

http://jsfiddle.net/zYrS8/

or even more compact and unreadable:

var randNum = null;
function getRand() {
    return randNum = (randNum == null?0:Math.round(Math.random()));
}

Maybe I don't understand your but give this a shot:

var randNum = 0;
function GetRandom()
{
  if (randNum == 0){
  alert ('0');
  } else {
  alert ('1');
  }
  randNum  = Math.floor(Math.random() * 3);
}
GetRandom();
GetRandom();
GetRandom();