Copying text to the clipboard shouldn't be hard. It shouldn't require dozens of steps to configure or hundreds of KBs to load. But most of all, it shouldn't depend on Flash or any bloated framework.
Internally, we need to fetch all elements that matches with your selector and attach event listeners for each one. But guess what? If you have hundreds of matches, this operation can consume a lot of memory.
For this reason we use [event delegation](http://stackoverflow.com/questions/1687296/what-is-dom-event-delegation) which replaces multiple event listeners with just a single listener. After all, [#perfmatters](https://twitter.com/hashtag/perfmatters).
We're living a _declarative renaissance_, that's why we decided to take advantage of [HTML5 data attributes](https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Using_data_attributes) for better usability.
A pretty common use case is to copy content from another element. You can do that by adding a `data-clipboard-target` attribute in your trigger element.
Truth is, you don't even need another element to copy its content from. You can just include a `data-clipboard-text` attribute in your trigger element.
If you don't want to modify your HTML, there's a pretty handy imperative API for you to use. All you need to do is declare a function, do your thing, and return a value.
For instance, if you want to dynamically set a `target`, you'll need to return a Node.
```js
new Clipboard('.btn', {
target: function(trigger) {
return trigger.nextElementSibling;
}
});
```
If you want to dynamically set a `text`, you'll return a String.
This library relies on both [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection) and [execCommand](https://developer.mozilla.org/en-US/docs/Web/API/Document/execCommand) APIs. The second one is supported in the following browsers.
Although copy/cut operations with [execCommand](https://developer.mozilla.org/en-US/docs/Web/API/Document/execCommand) aren't supported on Safari yet (including mobile), it gracefully degrades because [Selection](https://developer.mozilla.org/en-US/docs/Web/API/Selection) is supported.
That means you can show a tooltip saying `Copied!` when `success` event is called and `Press Ctrl+C to copy` when `error` event is called because the text is already selected.