Countdown timer every 3 days
<p>I'm a little confused. I need to get the 1st day of the month should start counting for 3 days. By the time the expiration restarted.</p>

<p><div class="snippet" data-lang="js" data-hide="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var today = new Date(),
    end = new Date( today.getFullYear(), today.getMonth(), today.getDate() + 3 );

var timer = setInterval(function() {
  var differenceTime, dd, hh, mm, ss, str;

  if ( ( new Date().getDate() == end.getDate() ) || ( new Date().getDate() == 1 ) ) {
    end = new
  } else {
    differenceTime = end - new Date();

    dd = parseInt(differenceTime / (1000 * 60 * 60 * 24));
    hh = parseInt(differenceTime / (60 * 60 * 1000)) % 24;
    mm = parseInt(differenceTime / (1000 * 60)) % 60;
    ss = parseInt(differenceTime / 1000) % 60;

    document.querySelector('.days').innerHTML = format(dd);
    document.querySelector('.hours').innerHTML = format(hh);
    document.querySelector('.minutes').innerHTML = format(mm);
    document.querySelector('.seconds').innerHTML = format(ss);
  }
}, 1000);

function format(num) {
  return (9 &lt; num) ? num : "0" + num;
};</code></pre>
<pre class="snippet-code-css lang-css prettyprint-override"><code>&lt;div class="cowntdown"&gt;
  &lt;span class="days"&gt;&lt;/span&gt;
  &lt;span class="hours"&gt;&lt;/span&gt;
  &lt;span class="minutes"&gt;&lt;/span&gt;
  &lt;span class="seconds"&gt;&lt;/span&gt;
&lt;/div&gt;</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="cowntdown"&gt;
  &lt;span class="days"&gt;&lt;/span&gt;
  &lt;span class="hours"&gt;&lt;/span&gt;
  &lt;span class="minutes"&gt;&lt;/span&gt;
  &lt;span class="seconds"&gt;&lt;/span&gt;
&lt;/div&gt;</code></pre>
</div>
</div>
</p>

<p>Help make the right condition.</p>