The Christmas spirit hovered over the stock market at midday Friday, lifting stocks moderately in dull trading. The Dow Jones industrial average and the S&P 500 were at record highs. The Nasdaq was not far from a Nov. 28 intraday high of 4810.79, the index’s best level since March 2000. The Nasdaq led the way, up 0.6%; the S&P 500 gained 0.4% and the Dow climbed 0.3% in the stock market today.