In 1968 when the American public went to see the Broadway play Hair, they were stunned to encounter a band of youth as alien to them as beings from another planet. The American Tribal Love-Rock Musical, as it was called, was a wild extravaganza of feeling about generational conflict, sex, the draft, race, drugs, and Vietnam.

Who could possibly bring this dated musical to the screen with its zest intact? And could yesterday's euphoric view of hippies translate into a movie for today's more conservative audiences? Luckily for all of us, the right creative individuals were chosen for this project. They are both seasoned explorers of youth cultures. Milos Foreman, who charted the generation gap in Taking Off and made One Flew Over the Cukoo's Nest into a winning movie, was selected as director. And Michael Weller, the playright who probed the spectrum of youth behavior in Moonchildren was given the task of writing the screenplay.

The result of their combined efforts is the zaniest blend of song, dance, gesture, and parody to be brought to the screen since Godspell! John Savage stars as Claude, an Oklahoma cowboy who comes to New York for induction into the army. He is taken in and entertained by a band of flower children in Central Park. They include Berger (Treat Williams), a bright, ebullient, and fun-loving fellow; Jeannie (Annie Golden), a pop-eyed waif who is pregnant; Hud (Dorsey Wright), a finger-snapping youth; and Woof (Don Dacus), a golden haired hippie.

Two of the best musical numbers erupt with a primitive energy that characterizes the movie as a whole. Berger and company crash a suburban debutante party in order to introduce Claude to Sheila (Beverly D'Angelo) who he's seen riding a horse in Central Park. In an inspired bit of spontaneity, Berger leaps on the banquet table to sing and dance an ode to youthful liberty — "I've Got Life." The dishes are miraculously saved from his whirling feet. Even more important, he wins Sheila over to their cause.

Another lively production number is "Black Boys, White Boys" which pokes fun at ethnic, sexual, and social stereotyping. In this piece as in several others, Twyla Tharp's innovative choreography matches the kinetic energy of the movie.

The screen version of Hair takes on a life of its own most convincingly when Berger and his friends decide to visit Claude at an Army training camp in Nevada. Standing in for Claude on base while the cowboy says goodbye to Sheila, Berger ends up having to go where he hadn't planned to go. Fellow feeling and fellowship are affirmed in a most moving way.

The ensemble work of Hair's cast is something to celebrate, especially the joie de virvre of Treat Williams' Berger, the wholesome naiveté of John Savage's Claude, and the appealing beauty of Beverly D'Angelo's Sheila. The fluid artistry of Miroslav Ondricek's cinematography conveys the magical mystery tour feel of the story as a whole. And the jubilant rock score by Galt MacDermot, Gerome Ragni, and James Rado retains all of its original gusto. Hair is a giddy elixir sure to send you from the theater with a happy natural high.