This is an interface for `removeEventListener`, with the main difference being that you don't have to pass a function as a second argument. And when no second argument is passed, all functions associated with the event will be removed.

```javascript
var element = el('div');

function logToConsole() {
  console.log('click');
}

element.on('click', logToConsole);
```

By clicking on `element` 'click' will be logged to the console.

```javascript
element.off('click', logToConsole);
```
In this example, we are attaching 3 functions to `element`

```javascript
element.on('click', click1);
element.on('click', click2);
element.on('click', click3);
```
We will now remove all event listeners attached to the `click` event by passing nothing as a second argument.

```javascript
element.off('click');
```