<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Graphviz.dart</title>
    <style>
    #input {
      width: 500px;
      height: 300px;
    }
    </style>
  </head>
  <body>
    <p><textarea id="input"></textarea></p>

    <p>
      <label>Output format:</label>
      <select id="format">
        <option>dot</option>
        <option>plain</option>
        <option selected>svg</option>
        <option>xdot</option>
      </select>
    </p>

    <p>
      <label>Layout engine:</label>
  