WASHINGTON — A new batch of television ads from the top Republican presidential hopefuls reflect the different pitches each is making to potential primary voters.

Mayor Giuliani is selling himself as a “tested” leader, Mitt Romney is the family man, and Michael Huckabee, in a tag team sketch with actor Chuck Norris, is sticking with what got him to the top tier of candidates in the first place: a sense of humor.

The former New York mayor launched just his second TV ad yesterday, unveiling a 30-second spot to air in Boston and New Hampshire that focuses on his experience at City Hall, as a U.S. attorney and as the third-ranking Justice Department official in the Reagan administration. As images of him in these positions flash across the screen, Mr. Giuliani touts his credentials. “I believe I’ve had the most leadership experience of anyone that’s running,” he says. Mr. Giuliani goes on to say: “I’ve been tested in a way in which the American people can look to me. They’re not going to find perfection, but they’re going to find somebody who has dealt with crisis almost on a regular basis and has had results. And in many cases, exceptional results.”

Mr. Romney’s 30-second, which is titled “American Family” and will run in Iowa and New Hampshire, features the former Massachusetts governor along with his wife, Ann, and images of his children. Its focus on the tight-knit Romney family draws an implicit contrast with Mr. Giuliani, who has been divorced twice and whose children have not participated in his campaign.

Mr. Huckabee’s ad, his first of the campaign, highlights an endorsement by action star Chuck Norris and employs the same folksy humor that has helped the former Arkansas governor surge to second in the Iowa polls. “My plan to secure the border,” Mr. Huckabee says to open the 60-second spot, “Two words: Chuck Norris.”