<div id="nocolor" class="common">背景色を持たないボックス</div>
<div id="bgcolor" class="common">背景色を持つボックス</div>
div.common {
  font-size: 20px;
  border: 2px solid #000000;
  padding: 20px;
}
div#bgcolor {
  background-color: #dddddd;
}
div#nocolor {
  margin: 40px;
}

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External JavaScript

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