Democratic gubernatorial candidate Lt. Gov. Ralph Northam, left, and GOP gubernatorial candidate Ed Gillespie.

Virginia Democratic gubernatorial candidate Ralph Northam released an ad calling on viewers to go online to compare his plan for economic growth, including bipartisan tax reform, with Republican rival Ed Gillespie’s plan for a tax cut for the wealthy.

But there is no detailed tax plan on Northam’s campaign website, aside from his call to lower grocery taxes for poor people and to create a bipartisan tax panel.

What’s more, Northam’s campaign said in April it would release a set of “guiding principles” on tax reform within a week. It never did, and a reference to that promise to voters was removed from the campaign’s website — until a reporter pointed it out.

“To keep Virginia’s economy growing, I want to build the best workforce in the nation, pass bipartisan tax reform focusing on the middle class, and invest in growing industries like biotech, cybersecurity and health care,” Northam says to the camera in the ad. “Ed’s plan is just another tax cut for the wealthy.” Northam then urges viewers to go online to compare for themselves.

Under the “taxes” tab of the policy section, Northam’s campaign website lists an April 24 news release announcing he wants to lower grocery taxes for low-income Virginians, without specifying how, and to create a bipartisan tax commission to work out the details of a tax code overhaul.

His campaign spokeswoman said the Democrat has repeatedly spoken about how he wants to remake the Virginia tax code to be more fair and simpler.

Meanwhile, Gillespie is calling for an across-the-board 10 percent cut in income tax rates — contingent on future economic growth and funded in part by unspecified cuts to the state budget. Democrats say it would be costly and disproportionately benefit the rich.

Republicans say Northam has been vague when it comes to taxes, while Gillespie has offered specifics.

“The Northam campaign called this ad ‘Go,’ but I think it should be called ‘Go where?’ because there is absolutely no place to go online where you can find any whiff of Ralph Northam’s tax reform plan,” Pete Snyder, Gillespie’s campaign chairman, said Friday in a conference call with reporters. “It doesn’t exist.”

Northam’s website does detail other parts of his economic vision, including subsidizing education and training for people who want to enter high-demand fields. While his campaign website deleted the reference to releasing guiding principles for tax reform, Northam has said in public appearances that raising taxes isn’t feasible and he wants a tax system that is more “fair” and simple.

A spokeswoman for Northam said the removal of the promise of a set of principles for tax changes was restored after a “copy error” and said Northam made those principles clear in debates and other statements.

“He has encouraged voters to compare visions, and his includes in-depth proposals for developing the workforce of the 21st century, taking on bipartisan tax reform, and maintaining our balanced budget and AAA bond rating while preserving investments to key priorities like health care and public education,” said Ofirah Yheskel, the spokeswoman. “Ed simply wants to give fiscally irresponsible tax breaks to the wealthy.”

Democrats and even some Republicans have questioned Gillespie’s claim that his plan for a 10 percent tax cut would save the “average” family of four $1,300 a year. That figure is based on an annual household income of $135,000.

Average household income in Virginia is about $90,000. Median income — the midpoint that some critics call a more meaningful measure since it is not skewed by extremes in wealth or poverty — is about $65,000.

Gillespie’s campaign has said the plan, which calls for phasing in the cut over three years, is based on calculations from the Beacon Hill Institute, a Boston think tank, and projections that average income will top $134,000 by 2021.

Northam has dismissed Beacon Hill as “a Koch-funded group that promotes skepticism of climate change,” in a reference to the conservative billionaire industrialists Charles and David Koch.