Below is my html looks like.....

```
<select onclick={this.handleClick}>
    <option key="1" value="aaa" data-plan-id="test"></option>
</select>

```

Below is my handleClick event code

```
console.log(e.target.value);   // this will output aaa

```

My question is how can I get the value from "data-plan-id" attribute which is "test"??