A/dabblet.css

## dabblet.css
/**
 * The first commented line is your dabblet’s title
 */

.a {
  width: 600px;
  height: 400px;
  background-color: #eba;
  position: relative;
}

.b {
  background: #bae;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  width: 200px;
  /*height: 200px;*/
  margin: auto;
  /*overflow: auto;  */
}

## dabblet.html
<!-- content to be placed inside <body>…</body> -->
<div class="a">
  <div class="b"></div>
</div>

## dabblet.js
// alert('Hello world!');

## settings.json
{"view":"separate","fontsize":"80","seethrough":"","prefixfree":"1","page":"all"}
	/**
	* The first commented line is your dabblet’s title
	*/

	.a {
	width: 600px;
	height: 400px;
	background-color: #eba;
	position: relative;
	}

	.b {
	background: #bae;
	position: absolute;
	top: 0;
	right: 0;
	bottom: 0;
	left: 0;
	width: 200px;
	/height: 200px;/
	margin: auto;
	/overflow: auto; /
	}
	<!-- content to be placed inside <body>…</body> -->
	<div class="a">
	<div class="b"></div>
	</div>