title: How to get value of textbox in React?
body: <p>I just started using React.js, and I'm just not sure whether there is a special way to get the value of a textbox, returned in a component like this:</p>
  
  <pre><code>var LoginUsername = React.createClass({
    render: function () {
      return (
        &lt;input type="text" autofocus="autofocus" onChange={this.handleChange} /&gt;
      )
    },
    handleChange: function (evt) {
      this.setState({ value: evt.target.value.substr(0, 100) });
    }
  });
  </code></pre>