title: React button not reacting to click event
body: <p>I am not sure why the 'click me' button is not updating state. The syntax looks good as I have no errors. But clicks are non-responsive. I don't think the handler is invoked at all. I am not able to figure this out. Thanks.</p>
  
  <pre><code>    class LoginForm extends React.Component {
    constructor(props){ 
      super(props);
      this.state = { 
        username: '',
        username2: "",
        buttonValue: "A"
      }; 
    }
    handleChange = event =&gt; {
      event.preventDefault();
      console.log(event.target.elements.username.value)
      this.setState({ username: event.target.elements.username.value }); 
    };
    handleChange2 = event =&gt; {  
      console.log(event.target.value)
      this.setState({ username2: event.target.value });   
    };
    handlechange3 = event =&gt; {
      console.log('clicked');
      this.setState({ buttonValue: event.target.value });
    }
    render() { 
      var x=1;
      return (
      &lt;div&gt; 
        &lt;form onSubmit={this.handleChange}&gt;{/* the input value is captured by event.target.elements.username.value by handleChange*/}
          &lt;label htmlFor="username"&gt;username&lt;/label&gt; 
          &lt;input
            type="text"
            name="username"          
          /&gt;
          &lt;input type='submit' /&gt; 
        &lt;/form&gt;
        &lt;label&gt;username2&lt;/label&gt; 
        &lt;input type='text' onChange={this.handleChange2} /&gt; {/* the input value is captured by event.target.value by handlechange2 */}
        &lt;br /&gt;
        &lt;button onClick={this.handleChange3}&gt;
          Click me
        &lt;/button&gt;
        &lt;h3&gt;Your username value is: {this.state.username}&lt;/h3&gt; 
        &lt;h3&gt;Your username2 value is: {this.state.username2}&lt;/h3&gt; 
        &lt;h3&gt;Your button value is: {this.state.buttonValue}&lt;/h3&gt;
      &lt;/div&gt;
        ); 
        }
    }
  </code></pre>