how does Shakespeare use dramatic irony?

Shakespeare uses dramatic irony in that all of the characters betrayed and destroyed by Iago trust him absolutely. Roderigo believes Iago to be his friend, assisting him to advance his relationship with Othello. Othello himself labels his ensign 'honest Iago' and trusts him with advising him on his wife. Desdemona uses Iago to help with reinstating Cassio to his position with Othello. Cassio allows Iago to talk him in to drinking and losing the respect and position he held with Othello. Finally Emilia is betrayed into giving Desdemona's handkerchief to Iago which brings about the chain of events which end in tragedy.

Each of these characters has seriously misplaced trust in Iago: the source of the dramatic irony in the play.

What is iago attitude towards women in the play