title: Remove all HTML <button> elements with regex
body: <p>I'm trying to build a program to run a function every time I press a button, and output the returned value. To do this, I use the following HTML:</p>
  
  <pre><code>&lt;h2&gt;Test Results:&lt;/h2&gt;
      &lt;strong&gt;&lt;span id='runs'&gt;0&lt;/span&gt; tests&lt;/strong&gt;&lt;br&gt;
      &lt;div id='testResults'&gt;
          &lt;button id='test' onClick='this.parentNode.innerHTML = initiatePlanB()'&gt;Begin&lt;/button&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>Here's the javascript:</p>
  
  <pre><code>var tests = document.getElementById('runs');
  var inner = document.getElementById('testResults').innerHTML;
  //Here's the part I can't figure out
  var wo = inner.replace(??????, '');
  var out = wo + '&lt;br&gt;&lt;strong&gt;Test #' + String(Number(tests.innerText) + 1) + '&lt;/strong&gt;&lt;br&gt;';
  tests.innerText = Number(tests.innerText) + 1;
  //More stuff here
  return out;
  </code></pre>
  
  <p>Basically, I need either a regex expression, or some other function that can remove any html tag and it's contents.</p>