Our DataTable is going to have four columns: Create a new function called prepareDataTable() to create and initialize the DataTable. To add a custom behavior when a data item is clicked on, we have to add a handler for the select event using the google.visualization.events.addListener method. Some uses of timeline charts include showcasing historical events in a creative way and the presentation of a business project’s plans. This is because we used a different row label for each row. And whether it's for school or business projects, or for something personal, these charts ensure goals are met, one step at a time. Mastering Web Technologies. 1 Solution. Toggle sidebar. You can add it at the end of the start function, after calling the draw method: See the Pen Google Charts Demo: Showing an Alert Message by SitePoint (@SitePoint) on CodePen. Timeline Chart and Annotated Timeline Chart are two different chart types. This chart is useful to show an interactive time series line chartin Google Sheets. The only difference in the last example is the start second.