The Offside Rule in Football
Offside can be called when an attacking player is in front of the last defender when the pass is played through to them. The offside area is designed to discourage players from simply hanging around the opponent’s goal waiting for a pass. To be onside they must be placed behind the last defender when the ball is played to them. If the player is in front of that last defender then he is deemed to be offside and free kick to the defending team will be called.
A player cannot be caught offside in their own half. The goalkeeper does not count as a defender. If the ball is played backwards and the player is in front of the last defender then he is deemed to be not offside.