A sales-tax exemption measure designed to encourage major online retailers to locate in New Jersey has been introduced in the Legislature.The bill would help alleviate disparities between online retailers, who are not required to collect New Jersey's 7 percent sales tax unless they have a physical presence in the state, and bricks-and-mortar stores, according to Democrats. Amazon.com, the world's biggest online retailer, is in talks to bring two warehouses to New Jersey in exchange for a delay in charging its Garden State customers sales tax. The deal could bring 1,500 full-time jobs to a state where unemployment has hovered around 9 percent. The legislation specifies that the jobs must go to New Jersey residents.