chromium/chrome/test/data/extensions/calculator_app/app/calculator.html

<html>
  <head>
    <title>Calculator</title>
    <link rel="stylesheet" type="text/css" href="style.css" />
  </head>
  <body>
    <div id="calculator">
      <div id="calculator-fade">
        <div id="calculator-fade-edge"></div>
        <div id="calculator-fade-gradient"></div>
      </div>
      <div id="calculator-display" role="log" aria-live="polite">
        <div class="equation">
          <span class="accumulator" aria-hidden="true"></span>
          <span class="operation">
            <span class="operator">
              <div class="spacer"></div>
              <div class="value"></div>
            </span>
            <span class="operand">0</span>
          </span>
        </div>
      </div>
      <div id="calculator-buttons">
        <div>
          <button class="clear" title="clear" data-button="clear"></button>
          <button class="negate" title="negate" data-button="negate"></button>
          <button class="divide" title="divide" data-button="divide"></button>
          <button class="multiply" title="multiply" data-button="multiply">
          </button>
          <button class="seven" title="seven" data-button="seven"></button>
          <button class="eight" title="eight" data-button="eight"></button>
          <button class="nine" title="nine" data-button="nine"></button>
          <button class="subtract" title="subtract" data-button="subtract">
          </button>
          <button class="four" title="four" data-button="four"></button>
          <button class="five" title="five" data-button="five"></button>
          <button class="six" title="six" data-button="six"></button>
          <button class="add" title="add" data-button="add"></button>
          <button class="one" title="one" data-button="one"></button>
          <button class="two" title="two" data-button="two"></button>
          <button class="three" title="three" data-button="three"></button>
          <button class="equals" title="equals" data-button="equals"></button>
          <button class="zero" title="zero" data-button="zero"></button>
          <button class="point" title="point" data-button="point"></button>
        </div>
      </div>
    </div>
  </body>
</html>