Javascript random on array without repeat [duplicate]

Answer 1

You can use a array for storing question that have been asked Check array every time during randomization and then select question

var track=new Array();

while(true)//loop until Unique number
{
    var randomQuiz=Math.floor(Math.random()*quiz.length);

     if(track.indexOf(randomQuiz)==-1)//if you have got your unique random number
     {
        track.push(random);
        break;
     }
}

Edit: as Stephen P pointed out it may lead to performance issue, removing element from array is more logical thing to do as suggested by Brent Waggoner.