The Nasdaq Composite Index extended its intraday decline midday Friday, with the decline on the session erasing the benchmark’s weekly rise. The Nasdaq , most recently, was down 1.6% at 7,718, and on track for a weekly fall of 1.3%, according to FactSet data. The slump comes as shares of tech and internet-related companies have taken it on the chin over the past few days, highlighted by a historic decline in shares of Facebook Inc. shares on Thursday and a plunge in Twitter Inc.’s shares . Both have fallen following quarterly results that disappointed the market. Meanwhile, the Dow Jones Industrial Average was off about 0.3%, while the S&P 500 index slipped by 0.7%. Both of those indexes were holding onto their weekly gains of nearly 1.5% and 0.6%, respectively. A weekly decline for the Nasdaq, if it holds, would mark the second straight such loss for the gauge, while the Dow and S&P 500 are on track for four straight weekly advances.