Stocks battled back to narrow gains Friday afternoon after a weak open. The S&P 500 climbed back above the break-even line, up 0.2%. The Dow Jones industrial average also added 0.2%. The Nasdaq, which earlier appeared headed for a third straight loss, rebounded to a 0.1% advance. Volume was running lower on both major exchanges vs. Thursday’s pace. Priceline (PCLN) slid almost 3% in heavy volume. The stock broke out Aug.