Javascript generate random unique number every time

Question

Ok so i need to create four randomly generated numbers between 1-10 and they cannot be the same. so my thought is to add each number to an array but how can I check to see i

Answer 1

Here are a couple versions using Matt's grabBag technique:

function getRandoms(numPicks) {
    var nums = [1,2,3,4,5,6,7,8,9,10];
    var selections = [];

    // randomly pick one from the array
    for (var i = 0; i < numPicks; i++) {
        var index = Math.floor(Math.random() * nums.length);
        selections.push(nums[index]);
        nums.splice(index, 1);
    }
    return(selections);
}

You can see it work here: http://jsfiddle.net/jfriend00/b3MF3/.

And, here's a version that lets you pass in the range you want to cover:

function getRandoms(numPicks, low, high) {
    var len = high - low + 1;
    var nums = new Array(len);
    var selections = [], i;
    // initialize the array
    for (i = 0; i < len; i++) {
        nums[i] = i + low;
    }

    // randomly pick one from the array
    for (var i = 0; i < numPicks; i++) {
        var index = Math.floor(Math.random() * nums.length);
        selections.push(nums[index]);
        nums.splice(index, 1);
    }
    return(selections);
}

And a fiddle for that one: http://jsfiddle.net/jfriend00/UXnGB/