How do I send data from React to Node server and back result to React?
<p>How may I send data from React to Node server and back result to React?
I have form on react, and have some data from form, I want to send this data to node server change this data and return result to react.</p>

<p><strong>React code:</strong></p>

<pre><code>var Exp = React.createClass({
getInitialState: function () {
    return {count: ""};
},

handleChange: function (event) {
    this.setState({count: event.target.value});
},
render: function () {
    return &lt;div&gt;
        &lt;h1&gt;Count: {this.state.count}&lt;/h1&gt;

        &lt;form method="post"&gt;
            &lt;input type="text" onChange={this.handleChange}/&gt;
            &lt;button onClick={this._onChange}&gt;Submit&lt;/button&gt;
        &lt;/form&gt;
    &lt;/div&gt;;
},
_onChange: function (event) {
    event.preventDefault();
    console.log("count: " + this.state.count);
}});React.render(&lt;Exp /&gt;, document.getElementById('container'));
</code></pre>

<p><strong>Node:</strong></p>

<pre><code>var express = require('express');
var mathjs = require('mathjs');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser());
app.get('/', function (req, res) {

var html = '&lt;form action="/" method="post"&gt;' +
    '&lt;input type="text" name="expression"  /&gt;' +
    '&lt;br&gt;' +
    '&lt;button type="submit"&gt;Submit&lt;/button&gt;' +
    '&lt;/form&gt;';

res.send(html);});

app.post('/', function (req, res) {

var expResult = mathjs.eval(req.body.expression);

var html = 'Result: ' + expResult + '.&lt;br&gt;' +
    '&lt;a href="/"&gt;Try again.&lt;/a&gt;';
res.send(html);});

app.listen(3333);
</code></pre>