Thousands of Jersey City teachers walked off the job today to protest stalled contract negotiations, leading to a chaotic day that saw boisterous protests outside city schools and a judge ordering teachers to get back to their classrooms on Monday morning.

Students all over Jersey City skipped class to join their teachers on the picket line. Teachers at McNair Academic High School yelling "scab" tried to block substitute teachers from entering the school. And hundreds of teachers marched to the school district's Claremont Avenue headquarters in the late morning as a stereo blasted Twisted Sister's "We're Not Gonna Take It."

The work stoppage came after months of failed negotiations between the Jersey City Education Association -- the 4,000-member union representing the teachers and other school employees -- and the Jersey City Board of Education. The strike was called late Thursday when a marathon school board meeting ended with no deal.

Teachers here have worked under an expired contract since Sept. 1 and are demanding lower health care costs. They say Chapter 78, New Jersey's 2011 law that revamped how public employees pay for their health benefits, has sharply curtailed their take-home pay.

"I've been in the system for 20 years and I'm finally making a decent salary and now I'm paying $1,400 a month for premiums," a 53-year-old physical education teacher at McNair told The Jersey Journal this morning.

Schools remained open for a half-day Friday, with teachers replaced by substitutes. One school official said the schools had 100 substitutes for 3,500 vacant positions.

Reaction from parents on Friday was mixed. Lizzie Skurnick told The Jersey Journal as she dropped her preschooler off at School 5 in Downtown Jersey City that she supports the teachers' efforts.

"A strike is disruptive, but that's the point," Skurnick said.

Heather Wilson described confusion at School 26 in the Heights when her husband dropped off their daughter for school. A crossing guard there told parents that school was closed, while the principal said she had just three substitute teachers for the school's roughly 350 students.

"Completely in support of the teachers, but this is so unorganized for parents and students," Wilson said.

The day was largely free of major incidents. Police were called to a fight at Dickinson High School. Videos posted on social media showed middle schoolers trashing a classroom.

A win for the teachers in this dispute would have statewide implications, as unions across New Jersey could cite Jersey City in their efforts to achieve lower health care costs.

"Quality, affordable health care is a fundamental right for everyone," JCEA President Ron Greco said in Friday morning's statement announcing the strike. "My members are prepared to step up and take on this fight for everyone, knowing full well that it will be a long, difficult process."

School officials have said its budget does now allow the district to spend any more for workers' health benefits. The district spent $98.9 million in 2017-18 on health benefits. The employee share of that was $19.9 million. The district's total budget is $682 million.

The nine-member school board has met three times this week in an effort to come to a deal, most recently on Thursday, when it convened until 12:30 a.m. Friday. It voted 4-2 to approve a contract offer — three board members cannot vote because they were endorsed by the teachers union in November's school elections — but by that time teachers had already been told the strike was on.

Negotiations resumed at 9 a.m. Friday but "talks broke down" before noon, according to a lawyer for the school district.

"We are no doubt disappointed with the JCEA leadership's reckless and irresponsible decision to strike work," Board of Education President Sudhan Thomas said in an email. "The JCEA leadership's actions will cause immense hardship to the 30,000 students we serve, the parents, the citizens of Jersey City and create additional pressure on the district while we are combating a $70 million shortfall for our budget 2018-2019."

After talks broke down Friday morning, the school district asked Hudson County Superior Court Judge Barry P. Sarkisian to issue an injunction ordering Jersey City teachers to end their strike. During an hourlong hearing in Sarkisian's Jersey City courtroom, school district attorney Lester Taylor noted that New Jersey law prohibits public sector unions from going on strike.

An attorney with the JCEA argued that Sarkisian did not have to act today, noting that schools remained open today even with teachers striking. But Sarkisian told him, "I do find losing one day of education that's constitutionally mandated to students, our 30,000 students here in the city of Jersey City, constitutes irreparable harm to those students."

Sarkisian agreed and issued the order for teachers to return to work Monday. It's not clear whether teachers will comply. In 1998, the year of the last teacher strike, the union initially ignored a similar judicial order.

School district spokeswoman Maryann Dickar said, "The board remains committed to finding a resolution."

Neither side has shared details about their contract offers. The board's deal, according to Mayor Steve Fulop, offers teachers a 7 percent pay hike over the next two years. A JCEA spokeswoman did not dispute those are the terms, but declined to comment, saying that negotiating in public "hinders the process."

Rebecca Kolins Givan is an associate professor in the Rutgers School of Management and Labor Relations who studies labor relations in public education. She said today's action is part of a "strike wave" that started with West Virginia's statewide teacher strike, which ended March 6 after nine days.

Teachers in Oklahoma, Arizona and Kentucky may also walk off the job.

"Teachers have realized that business as usual is not getting them what they need," Givan told The Jersey Journal.

Terrence T. McDonald may be reached at tmcdonald@jjournal.com. Follow him on Twitter @terrencemcd. Find The Jersey Journal on Facebook.