The present invention relates to a cover for a container opening (1) having a flexible web (3) one end of which is movable from a first edge of the opening (1) towards a second edge of the opening (1) in order to close the opening by means of the web (3), wherein the web (3) is lockable in at least one position covering the container opening in whole or in part and wherein the first end of a flexible pulling element (5) is fastened to the first end of the flexible web movable over the opening.In order to provide a pulling element for a cover opening which allows closing of the container opening it is provided according to the invention that the pulling element is fastened by its second end to the container (6) at or in proximity to that edge of the container opening (1) which is closest to the first end of the flexible web in the open state.