gecko-dev/layout/style/test/visited_image_loading.sjs

function handleRequest(request, response)
{
  response.setHeader("Cache-Control", "no-cache", false);
  var query = request.queryString;
  switch (query) {
    case "reset":
      response.setHeader("Content-Type", "application/ecmascript", false);
      setState("1l", "");
      setState("1v", "");
      setState("2l", "");
      setState("2v", "");
      break;
    case "1l":
    case "1v":
    case "2l":
    case "2v":
      setState(query, getState(query) + "load");
      response.setStatusLine("1.1", 302, "Found");
      // redirect to a solid blue image
      response.setHeader("Location", "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12NgYPgPAAEDAQDZqt2zAAAAAElFTkSuQmCC");
      response.setHeader("Content-Type", "text/plain", false);
      break;

    case "waitforresult":
      response.setHeader("Content-Type", "application/ecmascript", false);
      response.write("var start = Date.now();\n");
      // fall through!

    case "waitforresult-internal":
      response.setHeader("Content-Type", "application/ecmascript", false);
      response.write("if ('" + getState("1l") + "' == 'load' && '" +
                     getState("1v") + "' == '' && '" +
                     getState("2l") + "' == 'load' && '" +
                     getState("2v") + "' == '') { \n");
      response.write("setTimeout(function() {\n");
      response.write("var s = document.createElement('script');\n");
      response.write("s.src = 'visited_image_loading.sjs?result';\n");
      response.write("document.body.appendChild(s);");
      response.write("}, Math.max(100, 2 * (Date.now() - start)));\n");
      response.write("} else setTimeout(function() {\n");
      response.write("var s = document.createElement('script');\n");
      response.write("s.src = 'visited_image_loading.sjs?waitforresult-internal';\n");
      response.write("document.body.appendChild(s);");
      response.write("}, 10);\n");
      break;

    case "result":
      response.setHeader("Content-Type", "application/ecmascript", false);
      response.write("is('" + getState("1l") +
                     "', 'load', 'image 1l should have been loaded once')\n");
      response.write("is('" + getState("1v") +
                     "', '', 'image 1v should not have been loaded')\n");
      response.write("is('" + getState("2l") +
                     "', 'load', 'image 2l should have been loaded once')\n");
      response.write("is('" + getState("2v") +
                     "', '', 'image 2v should not have been loaded')\n");
      response.write("SimpleTest.finish()");
      break;
  }
}