SOURCE

var nums = [2, 7, 11, 15], target = 9;
console.log(twoSum(nums,target));
function twoSum (nums, target) {
  for (var i = 0; i < nums.length; i++) {
    for (var j = i + 1; j < nums.length; j++) {
      if ((nums[i] + nums[j]) == target) {
        return [i,j];
      }
    }
  }
  return false;
}