Hollywood starlets Eva Longoria, Scarlett Johannson and Kerry Washington took to the convention stage Thursday to try to persuade American voters to re-elect Barack Obama. The trio laid out ordinary early lives far from the bright lights of Hollywood with Longoria using her previous existence as a server at fast-food chain Wendy’s to have a dig at Obama’s Republican rival Mitt Romney. “The Eva Longoria who worked at Wendy’s flipping burgers — she needed a tax break. But the Eva Longoria who works on movie sets does not,” she said, pressing the charge that Romney is only interested in protecting the rich. Washington, the 35-year-old star of “Ray” and “The Last King of Scotland” was first up. “I’m here not just as an actress but as a woman, an African-American, a granddaughter of immigrants,” she said. “A person who could not have afforded college without the help of student loans and as one of millions of volunteers working to re-elect President Obama!” Next was 27-year-old Johansson, who told of her hard-scrabble childhood in New York City far from the bright lights of Hollywood.