title: onSubmit() is not working in React.js
body: <p>I have a <code>form</code> like below</p>
  
  <pre><code>&lt;form className="ui form" onSubmit={this.update}&gt;
       &lt;input type="text" defaultValue={this.props.element} onChange={this.handleChange1}/&gt;
       &lt;input type="button" value="Update" className="ui positive icon button"/&gt;
   &lt;/form&gt;
  </code></pre>
  
  <p>My update function is like below</p>
  
  <pre><code>update = event =&gt; {
     console.log('hello');
     event.preventDefault();  
  }
  </code></pre>
  
  <p>But it is not working.</p>