<html style="margin: 0;">
  <head>
    <title>Minimal WebGL Example</title>
    <!-- This use of <script> elements is so that we can have multiline text
         without quoting it inside of JavaScript; the web browser doesn't
         actually do anything besides store the text of these. -->
    <script id="shader-fs" type="x-shader/x-fragment">
      precision highp float;
      varying vec4 v_color;
      void main(void) {