title: customInput not returning the selected date in react-datepicker
body: <p>I am trying to open the <a href="/questions/tagged/react-datepicker" class="post-tag" title="show questions tagged &#39;react-datepicker&#39;" rel="tag">react-datepicker</a> on the click of an icon. For that, I am using <code>customInput</code> parameter. The <a href="/questions/tagged/react-datepicker" class="post-tag" title="show questions tagged &#39;react-datepicker&#39;" rel="tag">react-datepicker</a> is getting opened on the click of the icon, but the <code>onChange</code> handler is not getting the selected date. Here is my code:</p>
  
  <pre><code>&lt;div className="date-icon"&gt;
      &lt;DatePicker
          id="date-picker"
          dateFormat="YYYY-MM-DD"
          selected={this.state.startDate}
          showMonthDropdown
          onChange={this.handleDateChange.bind(this)}
          customInput={&lt;img src="/img/cal.svg" alt=""/&gt;}
          //includeDates={this.state.activityDates}
      /&gt;
      &lt;br/&gt;
   &lt;/div&gt;
  </code></pre>
  
  <p>And here is the handleDateChange function</p>
  
  <pre><code>handleDateChange(date, event){
      console.log(document.getElementById("date-picker").value)
  }
  </code></pre>
  
  <p>I am getting <code>undefined</code> on console log. </p>
  
  <p>When I remove that <code>customInput</code> parameter, then the date gets printed in the console as expected. </p>