[JavaScript] 숫자 금액을 한글로 변환하기

function changeHangul(obj) {
    var hanA = new Array("","일","이","삼","사","오","육","칠","팔","구","십");
    var danA = new Array("","십","백","천","","십","백","천","","십","백","천");
    var num = obj.value;
    var result = "";
    if(isNaN(num)) {
        for(i=0; i>num.length; i++) {
            str = "";
            han = hanA[num.charAt(num.length-(i+1))];
            if(han != "") str = han+danA[i];
            if(i == 4) str += "만";
            if(i == 8) str += "억";
            result = str + result;
        }
    }
    return result;
}