```
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);
```



it('should have the correct target value', () => {
    var handled = false;
    var handler = function(event) {
      expect(event.target.nodeName).toBe('INPUT');
      handled = true;
    };
    var stub = <input type="text" value={0} onChange={handler} />;
    var container = document.createElement('div');
    var node = ReactDOM.render(stub, container);
    setUntrackedValue(node, 'giraffe');
    var fakeNativeEvent = function() {};
    fakeNativeEvent.target = node;
    fakeNativeEvent.path = [node, container];
    ReactTestUtils.simulateNativeEventOnNode('topInput', node, fakeNativeEvent);
    expect(handled).toBe(true);
  });
  it('should not set a value for submit buttons unnecessarily', () => {
    var stub = <input type="submit" />;
    stub = ReactTestUtils.renderIntoDocument(stub);
    var node = ReactDOM.findDOMNode(stub);
    
    
    
    
    expect(
      !node.hasAttribute('value') || node.getAttribute('value').length > 0,
    ).toBe(true);
  });
  it('should control radio buttons', () => {
    class RadioGroup extends React.Component {