Discussion on: Challenge: find 'Kaprekar numbers'

function getSubInt(str, start, end){
    if(end == undefined)
        return parseInt(str.substring(start)) || 0;
    return parseInt(str.substring(0, end)) || 0;
}

function getKaprekar(max){
    var kaprekar = [], count = 0;

    for(var i = 1; count < max; i++){
        var sqr = (i * i).toString();
        var middle = (sqr.length / 2);

        if((getSubInt(sqr, 0, middle) + getSubInt(sqr, middle)) === i){
            kaprekar.push(i);
            count++;
        }
    }

    return kaprekar;
}

console.log(getKaprekar(8).toString());