{{</* tab */>}}**JSON**: JavaScript Object Notation (JSON) is a standard text-based format for representing structured data based on JavaScript object syntax.{{</* /tab */>}}
{{</* tab */>}}**YAML**: YAML is a human-readable data serialization language.{{</* /tab */>}}
{{</* tab */>}}**TOML**: TOML aims to be a minimal configuration file format that's easy to read due to obvious semantics.{{</* /tab */>}}
{{</* /tabs */>}}
```
### Specify Selected Index
Use `defaultIndex` property to specify the selected tab. The index starts from 0.
{{</* tab */>}}**JSON**: JavaScript Object Notation (JSON) is a standard text-based format for representing structured data based on JavaScript object syntax.{{</* /tab */>}}
{{</* tab */>}}**YAML**: YAML is a human-readable data serialization language.{{</* /tab */>}}
{{</* tab */>}}**TOML**: TOML aims to be a minimal configuration file format that's easy to read due to obvious semantics.{{</* /tab */>}}
{{< tab >}}**JSON**: JavaScript Object Notation (JSON) is a standard text-based format for representing structured data based on JavaScript object syntax.{{< /tab >}}
{{< tab >}}**YAML**: YAML is a human-readable data serialization language.{{< /tab >}}
{{< tab >}}**TOML**: TOML aims to be a minimal configuration file format that's easy to read due to obvious semantics.{{< /tab >}}
Tabs with the same list of `items` can be synchronized. When enabled, selecting a tab updates all other tabs with the same `items` and remembers the selection across pages.
Enable globally in your `hugo.yaml` under the `page` section:
```yaml {filename="hugo.yaml"}
params:
page:
tabs:
sync: true
```
With this enabled the following two tab blocks will always display the same selected item: