How to get the ReactJS element inside componentDidMount()?
<p>I have 4 instances of a certain React-class. After <code>componentDidMount()</code> I want to store the y-position of each instance.</p>

<p>How can I address the rendered element? I cannot use classname, because I have 4 elements of the same class with different positions.</p>

<p>My ReactJS component:</p>

<pre><code>const Col = React.createClass({
    componentDidMount: function() {
        //here address the actual rendered col-instance
    },

    render() {
        return (
            &lt;div className='col'&gt;
            &lt;/div&gt;
        );
    }
});
</code></pre>