After weeks of negative campaigning, New Jersey’s candidates for governor are looking for some high ground as they count down seven weeks until the election.

Democratic Gov. Jon Corzine is on the air with an upbeat commercial promoting the state as a place enjoying change for the better.

Polling shows that upbeat ad is trying to make a sale among some decidedly skeptical viewers — and the incumbent will have to win them over if he is to win his bid for a second term.

Corzine continues to trail his Republican challenger, former U.S. Attorney Chris Christie, in major polls. Christie led Corzine 47 percent to 39 percent among likely voters in the latest Monmouth University/Gannett New Jersey Poll. Independent Chris Daggett, a former EPA administrator, received 5 percent.

Christie’s campaign has been running ads that seek to connect with voter discontent and argue that a change in leadership is necessary to turn New Jersey around.

On Monday, Christie’s campaign launched a Web site, that mimics social networking sites and invites people to upload their own video commentary.

“The people of New Jersey are frustrated with the direction our state is headed under Jon Corzine ’s leadership and It’sMyNJ.com provides the opportunity for their voices to be heard,” Christie spokeswoman Maria Comella said in a statement.

Corzine’s commercial describes the governor as having created an economic recovery plan that’s starting to work. “Thousands of new private sector jobs — bucking the national trend,” the ad says. “He cut $4 billion in spending and delivered more property tax relief than any governor.”

Christie’s campaign chairman, state Sen. Joe Kyrillos, said the ad struck him “as proof that this person is really out of touch with reality,” and what voters ought to consider instead are the state’s unemployment rate — 9.3 percent in July, near the national unemployment rate of 9.4 percent, according to the Bureau of Labor Statistics.

The state also ranks in the top 10 in home foreclosures, according to RealtyTrac’s latest report.

Christie has been blaming the Corzine administration for high taxes and high government spending. More of the campaign’s back-and-forth, though, has been on the topic of corruption and ethics.

Democrats began hammering Christie’s reputation as a corruption-buster even before he clinched the June 3 GOP nomination. Several weeks later, Christie was called to Washington, D.C., to testify before a House subcommittee on his awarding of federal contracts while serving as a federal prosecutor.

More recently, Democrats hit out at Christie for failing to disclose a $46,000 loan to a subordinate during that same period of time.