[解決済み] JavaScriptを使用してHTML要素を含まない純粋なテキストを取得する方法は？

// my hacky approach:
function get_content() {
  var html = document.getElementById("txt").innerHTML;
  document.getElementById("txt").innerHTML = html.replace(/<[^>]*>/g, "");
}
// Gabi's elegant approach, but eliminating one unnecessary line of code:
function gabi_content() {
  var element = document.getElementById('txt');
  element.innerHTML = element.innerText || element.textContent;
}
// and exploiting the fact that IDs pollute the window namespace:
function txt_content() {
  txt.innerHTML = txt.innerText || txt.textContent;
}

.A {
  background: blue;
}

.B {
  font-style: italic;
}

.C {
  font-weight: bold;
}

<input type="button" onclick="get_content()" value="Get Content (bad)" />
<input type="button" onclick="gabi_content()" value="Get Content (good)" />
<input type="button" onclick="txt_content()" value="Get Content (shortest)" />
<p id='txt'>
  <span class="A">I am</span>
  <span class="B">working in </span>
  <span class="C">ABC company.</span>
</p>