Two teenage boys who were about 15 years old approached the 55-year-old woman in the Safeway parking lot on Middlefield Road around 5:30 p.m., police Agent Dan Ryan said.
The boys circled the woman on their bikes, Ryan said. One biked away and the other grabbed the woman's purse.
The woman, who told police she has limited mobility and uses a cane to walk, smacked the boy with her cane, according to Ryan. The boy then dropped the purse and biked away.
Police did not receive a report of the attempted robbery until the next day, Ryan said.
Ryan said the attempted robbery was not connected to the city's spate of recent robberies, "unless inspired by them somehow."