src/shell.html

<!doctype html>
<html lang="en-us">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Emscripten-Generated Code</title>
    <style>{{{ SHELL_CSS }}}</style>
  </head>
  <body>
    <a href="http://emscripten.org">{{{ SHELL_LOGO }}}</a>

    <div class="spinner" id='spinner'></div>
    <div class="emscripten" id="status">Downloading...</div>

    <span id='controls'>
      <span><input type="checkbox" id="resize">Resize canvas</span>
      <span><input type="checkbox" id="pointerLock" checked>Lock/hide mouse pointer &nbsp;&nbsp;&nbsp;</span>
      <span><input type="button" value="Fullscreen" onclick="Module.requestFullscreen(document.getElementById('pointerLock').checked, 
                                                                                document.getElementById('resize').checked)">
      </span>
    </span>

    <div class="emscripten">
      <progress value="0" max="100" id="progress" hidden=1></progress>
    </div>

    <div class="emscripten_border">
      <canvas class="emscripten" id="canvas" oncontextmenu="event.preventDefault()" tabindex=-1></canvas>
    </div>
    <textarea id="output" rows="8"></textarea>

    <script type='text/javascript'>
      var statusElement = document.getElementById('status');
      var progressElement = document.getElementById('progress');
      var spinnerElement = document.getElementById('spinner');

      var Module = {
        print: (function() {
          var element = document.getElementById('output');
          if (element) element.value = ''; // clear browser cache
          return (...args) => {
            var text = args.join(' ');
            // These replacements are necessary if you render to raw HTML
            //text = text.replace(/&/g, "&amp;");
            //text = text.replace(/</g, "&lt;");
            //text = text.replace(/>/g, "&gt;");
            //text = text.replace('\n', '<br>', 'g');
            console.log(text);
            if (element) {
              element.value += text + "\n";
              element.scrollTop = element.scrollHeight; // focus on bottom
            }
          };
        })(),
        canvas: (() => {
          var canvas = document.getElementById('canvas');

          // As a default initial behavior, pop up an alert when webgl context is lost. To make your
          // application robust, you may want to override this behavior before shipping!
          // See http://www.khronos.org/registry/webgl/specs/latest/1.0/#5.15.2
          canvas.addEventListener("webglcontextlost", (e) => { alert('WebGL context lost. You will need to reload the page.'); e.preventDefault(); }, false);

          return canvas;
        })(),
        setStatus: (text) => {
          Module.setStatus.last ??= { time: Date.now(), text: '' };
          if (text === Module.setStatus.last.text) return;
          var m = text.match(/([^(]+)\((\d+(\.\d+)?)\/(\d+)\)/);
          var now = Date.now();
          if (m && now - Module.setStatus.last.time < 30) return; // if this is a progress update, skip it if too soon
          Module.setStatus.last.time = now;
          Module.setStatus.last.text = text;
          if (m) {
            text = m[1];
            progressElement.value = parseInt(m[2])*100;
            progressElement.max = parseInt(m[4])*100;
            progressElement.hidden = false;
            spinnerElement.hidden = false;
          } else {
            progressElement.value = null;
            progressElement.max = null;
            progressElement.hidden = true;
            if (!text) spinnerElement.style.display = 'none';
          }
          statusElement.innerHTML = text;
        },
        totalDependencies: 0,
        monitorRunDependencies: (left) => {
          this.totalDependencies = Math.max(this.totalDependencies, left);
          Module.setStatus(left ? 'Preparing... (' + (this.totalDependencies-left) + '/' + this.totalDependencies + ')' : 'All downloads complete.');
        }
      };
      Module.setStatus('Downloading...');
      window.onerror = (event) => {
        // TODO: do not warn on ok events like simulating an infinite loop or exitStatus
        Module.setStatus('Exception thrown, see JavaScript console');
        spinnerElement.style.display = 'none';
        Module.setStatus = (text) => {
          if (text) console.error('[post-exception status] ' + text);
        };
      };
    </script>
    {{{ SCRIPT }}}
  </body>
</html>