Question: I want to retrieve the value of my checkbox when it is checked.

I am using this "<http://react-component.github.io/checkbox/>".

My code looks like this.

```
<div className="user_box">
    { check.map((values , i)=> {
        return <Checkbox
            name = "checkbox"
            onChange={this.checkvalue.bind(this)}
            value={values.username} 
        />
    })}
</div>

```

My function:

```
checkvalue(e){
    // var all_users = [];
    // var value = this.checkbox.value;
    // all_users.push(value);
    // console.log(all_users);

    console.log('checkbox checked:', (e.target.checked));
}

```

I'm not understanding how to retrieve the value of the checkbox.

Answer: 
you need to pass the "e, Synthetic event parameter to your handler" :

```
handleChange(e) {
  let isChecked = e.target.checked;
  // do whatever you want with isChecked value
}

render() {
  // ... your code here
  return (
    {/* your other jsx here */}
    <Checkbox otherProps onChange={e => this.handleChange(e)} />
    {/* your other jsx here */}
  );
}

```
Use the Synthetic event parameter, here is an example:

```
const element1 = "boy";
const element2 = "girl";

<input
 type="checkbox"
 name={element1}
 value={element1}
 onChange={this.handleChange}
/>
<label for="element" style={{ fontSize: 35 }}>
{element2}
 </label>

<input
 type="checkbox"
 name={element2}
 value={element2}
 onChange={this.handleChange}
/>
<label for="element" style={{ fontSize: 35 }}>
{element2}
 </label>

handleChange = (e) => {
// to find out if it's checked or not; returns true or false
const checked = e.target.checked;

// to get the checked value
const checkedValue = e.target.value;

// to get the checked name
const checkedName = e.target.name;

//then you can do with the value all you want to do with it.
};

```