# Event Containers (JavaScript Scheduler) | DayPilot Pro for JavaScript Demo

> Event containers force events with the same container id to be rendered at the same vertical position within a row. Read more about [event containers](https://doc.daypilot.org/scheduler/event-containers/) [doc.daypilot.org].

## Links

- Canonical HTML: /demo/scheduler/eventcontainers.html
- Source HTML folder: /demo/scheduler/
- Catalog root: /demo/
- Catalog: /demo/llms.txt

## Source

### Inline demo script 1

```javascript
const dp = new DayPilot.Scheduler("dp", {
            startDate: "2026-01-01",
            days: 365,
            scale: "Day",
            timeHeaders: [
                {groupBy: "Month", format: "MMMM yyyy"},
                {groupBy: "Day", format: "d"}
            ],
            treeEnabled: true,
            resources: [
                {
                    name: "Locations", id: "G1", expanded: true, children: [
                        {name: "Room 1", id: "A"},
                        {name: "Room 2", id: "B"},
                        {name: "Room 3", id: "C"},
                        {name: "Room 4", id: "D"}
                    ]
                },
                {
                    name: "People", id: "G2", expanded: true, children: [
                        {name: "Person 1", id: "E"},
                        {name: "Person 2", id: "F"},
                        {name: "Person 3", id: "G"},
                        {name: "Person 4", id: "H"}
                    ]
                },
                {
                    name: "Tools", id: "G3", expanded: false, children: [
                        {name: "Tool 1", id: "I"},
                        {name: "Tool 2", id: "J"},
                        {name: "Tool 3", id: "K"},
                        {name: "Tool 4", id: "L"}
                    ]
                },
            ],
            onTimeRangeSelected: async args => {
                const modal = await DayPilot.Modal.prompt("New event name:", "New Event");
                dp.clearSelection();
                if (modal.canceled) {
                    return;
                }
                dp.events.add({
                    start: args.start,
                    end: args.end,
                    id: DayPilot.guid(),
                    resource: args.resource,
                    text: modal.result
                });
                dp.message("Created");
            },
            onBeforeEventRender: args => {
                if (args.data.container) {
                    args.data.html = `${args.data.text} (container: ${args.data.container})`;
                }
            },
            height: 350
        });
        dp.init();

        const app = {
            init() {
                this.loadEventData();
            },
            loadEventData() {
                // generate and load events
                const events = [
                    {
                        "start": "2026-01-07T00:00:00",
                        "end": "2026-01-12T00:00:00",
                        "id": "39441891-f564-8fc3-caf4-a2e892f804de",
                        "resource": "A",
                        "text": "New Event 1",
                    },
                    {
                        "start": "2026-01-11T00:00:00",
                        "end": "2026-01-15T00:00:00",
                        "id": "ce83a6d7-d8ff-ea0c-d149-4c37691b29da",
                        "resource": "A",
                        "text": "New Event 2",
                        container: 1
                    },
                    {
                        "start": "2026-01-17T00:00:00",
                        "end": "2026-01-22T00:00:00",
                        "id": "39fb5fba-d2cc-1c62-41a4-0b8df487f917",
                        "resource": "A",
                        "text": "New Event 3",
                        container: 1
                    }
                ];

                const links = [
                    {
                        from: "ce83a6d7-d8ff-ea0c-d149-4c37691b29da",
                        to: "39fb5fba-d2cc-1c62-41a4-0b8df487f917"
                    }
                ];

                dp.update({
                    events,
                    links
                });
            }
        };
        app.init();
```