NEWARK — The fifth-graders of Yolanda Bromfield’s digital-privacy class had just finished their lesson on ­online-offline balance when she asked them a tough question: How would they act when they left school and reentered a world of prying websites, addictive phones and online scams?

Susan, a 10-year-old in pink sneakers who likes YouTube and the mobile game “Piano Tiles 2,” quietly raised her hand. “I will make sure that I don’t tell nobody my personal stuff,” she said, “and be offline for at least two hours every night.”

Between their math and literacy classes, these elementary school kids were studying up on perhaps one of the most important and least understood school subjects in America — how to protect their privacy, save their brains and survive the big, bad Web.

Classes such as these, though surprisingly rare, are spreading across the country amid hopes of preparing kids and parents for some of the core tensions of modern childhood: what limits to set around technologies whose long-term effects are unknown — and for whom young users are a prime audience.

The course offered to Susan’s 28-student class at First Avenue School, a public neighborhood school in Newark, is part of an experimental curriculum designed by Seton Hall University Law School professors and taught by legal fellows such as Bromfield. It has been rolled out in recent months to hundreds of children in a dozen classrooms across New York and New Jersey.

Read the rest of The new lesson plan for elementary school: Surviving the Internet."