The overlay.js extension contains a set of API methods to simplify work with overlays. Read details about the Overlay extension in the article Extra Elements in Timeline Area.
The following methods are available via the gantt.ext.overlay object:
adds a new overlay into the Gantt Chart and returns its id. Takes a container with custom content as a parameter.
var overlay = gantt.ext.overlay.addOverlay(function(container){});
removes an overlay by its id
gantt.ext.overlay.deleteOverlay(id);
returns an array with ids of overlays added into the chart
var ids = gantt.ext.overlay.getOverlaysIds();
repaints the specified overlay. Takes the id of an overlay as a parameter.
gantt.ext.overlay.refreshOverlay(id);
shows an overlay by its id. Takes the id of an overlay as a parameter.
gantt.ext.overlay.showOverlay(id);
hides an overlay by its id
gantt.ext.overlay.hideOverlay(id);
checks visibility of the specified overlay. Returns true if the overlay is visible.
var isVisible = gantt.ext.overlay.isOverlayVisible(id);