# Configure a component and reconfigure it later
> Give a component default options, override them in the config attribute, react in configure() and change them at runtime with reconfigure().
Framework: jcomponent20
Product: jComponent 20 (jcomponent@20)
Language: en
Content-SHA256: 0029f1b2c2a136827eb199e9ed2afef07a7637807acf316edd4f61f7011cad76
Snapshot: c0700e321579725c5cf4f5ace1ad7d2866d1b4f93c24a63c0b41b6b7998e976c
Sources: jcomponent20@3fedd009a277f50fddc608b97afbec553b67c51b
Review: not-recorded
The second argument of `COMPONENT()` holds the default options. The `config` attribute of the element overrides them, and the declaration reads the merged values from `config`. Implement `self.configure(key, value)` to react when an option is set or changed. At runtime `self.reconfigure('key:value;key2:value2')` (or `CONFIG(selector, config)` for many components) changes options and calls `configure` for each changed key.
```html public/index.html
jComponent
```