Strong online sales and a boost from the World Cup helped pizza delivery firm Domino's post another bumper set of results.Profits jumped 30% to £17m, from £13.1m, in the half year. Sales for the 26 weeks ended 27 June 2010 grew by 20.8% to £237.1m (2009: £196.4m), driven by the growth in like-for-like sales in 553 mature stores of 13.7% (2009: 7.1% in 501 stores) and the opening of 19 new stores.Margins were boosted strong volumes, driven by price based promotions, and came in ahead of its long-term expectations. "We are delighted with our continued growth over the first 26 weeks of the current financial year. With free cash flows increasing and the completion of the current phase of our expansionary capital expenditure programme, we are well positioned to return surplus cash not required in the business to," it added.The interim increased 28.6% to 4.5p (2009: 3.5p).