Tax-free shopping on the Internet could be in jeopardy under a .

The bill would empower states to require online retailers to collect state and local for purchases made over the Internet. The sales taxes would be sent to the states where a shopper lives.

Under current law, states can only require stores to collect sales taxes if the store has a physical presence in the state. As a result, many online sales are essentially tax-free, giving a big advantage over brick-and-mortar stores.

The Senate voted 74 to 20 Monday to take up the bill. If that level of support continues, the Senate could pass the bill as early as this week.