`, but they have a special meaning. ### aka TBD ### hidden TBD ### data TBD ### dataOffset TBD ### dataLength TBD ### nestFor TBD ### nestIn TBD ## Special prefixes Values using special prefixes have special meanings based on the prefix itself. We can specify them in HTML code using the prefix followed by `-` (dash), and we can access them from JavaScript using the prefix followed by `_` (underscore). ### attr Normal HTML attribute that have an [expression](https://trillojs.dev/docs/reference/language#2-reactive-expressions-) in their value are available with this prefix in tag's [scope](https://trillojs.dev/docs/reference/language#3-visibility-scopes-). E.g.: ```html ``` will add a value `attr_lang` in the root scope. ### on These values contain event listeners for DOM events. E.g.: ```html ``` will assign the listener function to value on\_click in tag's [scope](https://trillojs.dev/docs/reference/language#3-visibility-scopes-), and will register it with its underlying DOM element. Using `:on-` attributes for registering DOM event handlers is recommended, so scopes can be added and removed as needed, with their event listener properly registered and unregistered, when [replicating](https://trillojs.dev/docs/reference/runtime#data) scopes or when using [conditional blocks](https://trillojs.dev/docs/reference/stdlib#on-off). > `:on-` event listeners are not related to the legacy `on...` HTML attributes, and are implemented with `addEventListener()` behind the scenes. ### handle These values contain handler expressions which are executed when and only when some other value changes. E.g.: ```html ``` The handler will only be executed only when `count` changes (including when it's initialized). Changes of the mode value won't execute it. This is in contrast with how reactive expressions normally work: they are re-evaluated when any of the values they reference changes. ### class These values let us add and remove class names in a scope's underlying DOM element. TBD ### style TBD ### did TBD ### will TBD ## Implementation values TBD ### \_\_id TBD ### \_\_dom TBD ### \_\_scope TBD ### \_\_outer TBD ### \_\_elementIndex TBD ### \_\_isLastElement TBD ### \_\_mixColors TBD ### \_\_regexMap TBD