this is how you can update getInitialState in your app.

React update getInitialState

var App = React.createClass({
  getInitialState: function() {
    return {
      text: 'this is initial state text',
    };
  },

  // update is a custom function we've created
  update: function(e) {
    // this.setState is the key to update text in this example
    this.setState({text: e.target.value});
  },

  render: function() {
    return (
    	<div>
    		<input type='text' onChange={this.update} />
    		<h1>{this.state.text}</h1>
    	</div>
    );
  },
});

React acted weird about some syntax stuff. Most notably, it didn't like that the input tag had more standard HTML5 simple closing tag. It expected ' /> ' instead.

Looks like tag closing rules from here also apply to HTML tags, not just components.