It was a simpler time, when Johnny Depp was new to Tiger Beat, when hair metal still ruled the airwaves and when Fox was an infant TV network with a bare handful of series  — “The Simpsons,” “America’s Most Wanted” and this silly cop confection called “21 Jump Street.”

Now, that teen friendly cop show has been updated and unleashed in the post “Hangover” era — when no joke is out of bounds, no language is too profane, no riff on drugs or sex is too extreme.

You’d expect a big screen version of “21 Jump Street,” the TV series that made Johnny Depp famous, to be a joke. And it is, a raunchy, violent and potty-mouthed farce that straddles the middle ground between “Starsky & Hutch” and “Superbad.” It’s “Project X” with pistols.

The cute young cops here aren’t Tiger Beat cute the way Depp and co-stars like Holly Robinson and Peter DeLuise were. And they’re self-aware. They’re incompetent, and they know it. New to the force, they haven’t even memorized the Miranda Rights speech.

“They always cut away on TV before they finish!” Jenko (Channing Tatum) complains.

In high school, he was the popular, handsome jock who “didn’t learn a thing” during his years there. Poor Schmidt (Jonah Hill) was the insecure, unathletic brainiac who always choked when the chips were down — asking a girl to the prom, for instance. Jenko used to pick on Schmidt.

But when they help each other get through the police academy, they become best buds. And being, as the captain in charge (Ice Cube) puts it, “Justin-Bieber/Miley Cyrus-looking,” they’re naturals for the revival of an old program — putting baby-faced cops back into high school to hunt down the dealers and suppliers of a deadly new drug — HFS. Nobody will suspect them, the chief assures them.

“They’re teenagers, man. They’re really stupid.”

Jenko is set to slide back into the Prom King status he enjoyed just a few years before, with Schmidt doomed to relive his chemistry whiz nobody liked years — “Embrace your stereotypes!”

But the idiots botch their assumed identities. Schmidt is now the alleged jock, Jenko the brains. And high school has changed in the seven years since they graduated. The enviro-nerd (Dave Franco) is king of the cool kids. Caring about schoolwork is cool, drama club is cool, and picking on a gay kid isn’t. (Jenko blames “Glee!” in one of the movie’s funniest and filthiest lines).

And even though they only have three basic rules to adhere to — find the supplier, don’t get expelled and don’t sleep with students or faculty — Jenko and Schmidt, alias Doug and Chad, screw things up.

The co-directors of the adorably irreverent and sweet animated hit “Cloudy With a Chance of Meatballs” stick pretty close to formula, here. Characters may joke about how lame it is to keep recycling old ideas in police work (and movies), but that doesn’t mean they don’t embrace it.

Hill does his usual chubby white kid talking ghetto smack. But Tatum (“The Vow”), given the chance to cut up and cut loose, dives into this head-first, mocking his good looks and playing the male bimbo thing to the max. Jenko’s report to the captain about high school today being the reverse of when jocks like him ran the show is angry, wounded and hilarious.

“It’s backwards and wrong and it must be stopped!”

Having the hunk hang out with science and sci-fi geeks — “KNEEL before Zod!” — is funny. Having the lovelorn nerd fall for his drama club “Peter Pan” co-star (Brie Larson) isn’t.

Like high school itself, “21 Jump Street” hits the wall about halfway in and even prom night can’t save it. They rely on profane tirades from Ice Cube (funny, you have to admit), yet another teen party that gets out of hand and over-the-top violence and lose track of these two guys living the reverse of their high school days.

And joking about how lame it is to recycle formulas, stereotypes and movie cliches doesn’t excuse you from using them as crutches, one after the other.

MPAA Rating: R, for crude and sexual content, Pervasive language, drug material, teen drinking and some violence.

Cast: Channing Tatum, Jonah Hill, Brue Larson, Dave Franco

Credits: Directed by Phil Lord and Chris Miller, scripted by Michael Bacall, based on the TV series. A Columbia/MGM release.

Running time: 1:49