```
render () {
  <input type="number" value={this.props.value} />
}
```

for example, when the original value is '.98', we need format it to '0.98'. but it is not  take effect。

```javascript
class Test extends React.Component {
 state = {
    value: '.98',
  }
 changeValue = () => {
    alert(0.98);
    this.setState({
      value: '0.98',
    });
  }

 render() {
    return <div>
      <input type="number" value={this.state.value} />
      <button onClick={this.changeValue}>changeValue</button>
    </div>;
  }
}

ReactDOM.render(<Test />, mountNode);
```



<TestCase.ExpectedResult>
          The field should read "2e4". The parsed value should read "20000"
        </TestCase.ExpectedResult>
        <NumberTestCase />
      </TestCase>
      <TestCase
          title="Exponent Form"
          description="Pressing 'e' at the end"
      >
        <TestCase.Steps>
          <li>Type "3.14"</li>
          <li>Press "e", so that the input reads "3.14e"</li>
        </TestCase.Steps>
        <TestCase.ExpectedResult>
          The field should read "3.14e", the parsed value should be empty
        </TestCase.ExpectedResult>
        <NumberTestCase />
      </TestCase>
      <TestCase
          title="Exponent Form"
          description="Supports pressing 'ee' in the middle of a number"
      >
        <TestCase.Steps>
          <li>Type "3.14"</li>
          <li>Move the text cursor to after the decimal place</li>
          <li>Press "e" twice, so that the value reads "3.ee14"</li>
        </TestCase.Steps>
        <TestCase.ExpectedResult>
          The field should read "3.ee14"
        </TestCase.ExpectedResult>