trimlog-ykonsole-chrome-ext.../popup.html

<!DOCTYPE html>
<html lang="NO">
<head>
  <style>
    button {
      height: 30px;
      width: 30px;
      outline: none;
    }
  </style>
</head>
<body>
<button id="changeColor" value="#FF0000">qqq</button>
<script src="popup.js"></script>
</body>
</html>