Movie musicals of the 1960s introduced the world to a whole new collection of composers and lyricists, starting with Leonard Bernstein and Steven Sondheim ("West Side Story"). Rodgers and Hammerstein and Lerner and Loewe still remained popular, but they no longer dominated the field.
Most of the movie musicals of the 1960s retained most of the songs from the original Broadway plays, but, occasionally, new songs were added or original songs were removed. Also, some movies had songs rearranged to create a more dramatic effect or to better fit the medium of film (for example, "Officer Krupke" and "Cool" were interchanged in the movie version of "West Side Story").
Many of the movie musicals had hit songs, but, in many cases, the songs were already known to many people from the success of the Broadway play (for example, "I Could Have Danced All Night" from "My Fair Lady").