Function timespan

timespan(json?): void
Sets the animation duration.
Parameters
- json: {
      days: number;
      label: string;
      type: string;
  } = ...
  - days: number
    number "1 | 3 | 7 | 30 | 365"
  - label: string
    string "1 day ... 1 year | selected route | all routes | realtime"
  - type: string
    string "days | route | routes | track | tracks | realtime"
Returns void
Example
```
// set the duration to one day
{
 "label": "1 day",
 "days": 1,
 "type": "days"
}

// set the duration to all routes
{
 "label": "all routes",
 "days": 1,
 "type": "routes"
}

// set the duration to realtime
{
 "label": "real time",
 "days": 1,
 "type": "realtime"
}
```