Good economic news is hard to come by these days. So when the January jobs report showed the economy added close to 250,000 jobs, all three stock markets responded with big gains. The Dow closed at 12,862.23, up 1.2 percent. That marked its best close since May 2008. The S&P was up 1.46 percent and the Nasdaq posted a 1.6 percent gain. The activity follows a strong January for the markets, all three of which ended the month up from where they started.