In Antigone by Sophocles, the Chorus, which consists of a group of Theban elders who are advisers to King Creon, performs three important roles. First, they provide information about what takes place offstage, filling in backstory or action that is necessary for the audience to understand the plot. For example, at the beginning of the play, they explain the battle that recently took place, where Eteocles and Polynices, Antigone's brothers, faced off for control of the city of Thebes and ended up killing each other. They introduce Creon as the new king.

The second role of the Chorus is to stand in for the audience, providing the response that the playwright intends the audience to have to the unfolding drama. Thus, at the beginning of the play, the elders are firmly on the side of Creon, expounding on the right of kings to make and enforce law. But as Antigone and Haemon make their arguments, the Chorus begins to waver. When Tiresias arrives and reveals the anger of the gods toward Creon's decree that Polynices should not be buried, the Chorus swings fully over to Antigone's side. At the end of the play, the Chorus wails, "Ah me, how all too late thou seemest to see the right!" This voices the feelings of the audience at the tragedies that have befallen Creon because of his pride.

Finally, the Chorus allows the playwright to show off the beauty of his language in lyrical odes. The Chorus recites several impressive odes, including the "Ode to Man" and the "Ode to Zeus," which display Sophocles's prowess as a poet. This elevated diction rewards the audience with a sophisticated level of entertainment that they can find nowhere else.

In Antigone, Sophocles makes effective use of the Chorus as a narrator, a stand-in for the audience, and a showcase for his poetic language.

The purpose of the chorus in Ancient Greek drama is to represent the perspective of ordinary people. It generally conveys the conventional wisdom of the time and represents the kind of common sense that the main characters don't typically show because they are so carried away in the extremes of their emotional experiences. The chorus' reactions also demonstrate the effect that the behavior of royal and noble characters has on the people that they rule or have control over. In this way, the audience members, who are not all royal or noble, can see how the events of the play might potentially relate to their own lives. Those who are of a higher class and are watching the play might also be brought to think about how their actions and experiences affect those over whom they have political control. Thus, the chorus serves as a device to prompt reflection in the audience.

The first thing to note is that Greek tragedy evolved out of choral performance. Having actors who played individual roles was an innovation that began within Sophocles' own lifetime. You could even argue that the chorus is the center of the drama.

The chorus first serves as a form of spectacle, as in ancient productions choral odes were sung with the chorus dancing as they sang. This song and dance was deeply rooted in tradition and religious ritual and thus emphasizes the sacred roots of tragedy. As Sophocles' plays were originally performed at a festival in honor of Dionysus, in a religious rather than secular context, the chorus functions to celebrate the gods and often expresses a particularly pious viewpoint, thinking about how the gods might be connected with or concerned about various events in the play. On a dramatic level, they often function as a narrative voice, explaining what happened before the start of the play and discussing events that occur offstage.

Finally, the chorus expresses the viewpoint of "everyman", of the society as a whole as an organic construct with certain beliefs and moral values. While both Creon and Antigone are outliers in their viewpoints, with Creon more rational and pragmatic than average and more an advocate of human rational law than tradition and Antigone more personally religious and devoted to family than average and more willing to rebel against human convention, the chorus expresses what would have been the "common sense" viewpoint of the period, against which we can judge more extreme positions. 

In ancient Greek drama, the chorus is a group that comments collectively on the play's action and context. The role of the chorus is to provide information not revealed in dialogue, such as context within mythology, narration, and the characters' thoughts.

In Antigone, the chorus consists of Theban elders. They provide background information connecting Antigone's story to other myths and comment on the play's action. The chorus in Antigone even participates in the action of the play occasionally; for example, at one point Creon consults them and they provide their support for his decision, although they later oppose Creon when he considers punishing Ismene. The play closes with a monologue by the Theban elders about how the gods' punishment can bring wisdom.

What is the function of the Chorus in Anouilh's version of "Antigone"?

The Chorus is ancient Greece provided necesarry information to the audience, and often worked as the conscience of the characters.  The Chorus in this version of Antigone serves as the voice of the playwrite herself.  It allows Anouilh to present her story in a specific way, which forces the audience to understand it in that way. 

The Chorus does this by introducing the characters, and telling the audience what their traits are and their importance is.  The audience can not be allowed to interpret for themselves - that might change the understanding of the play.  The Chorus also provides a dialogue on the nature of tragedy itself so that the audience understands why things are happening in the way they are.

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