viewer-snippet-mozPrintCallback-polyfill.html

<div id="mozPrintCallback-shim" hidden>
  <style>
@media print {
  #printContainer div {
    page-break-after: always;
    page-break-inside: avoid;
  }
}
  </style>
  <style scoped>
#mozPrintCallback-shim {
  position: fixed;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  z-index: 9999999;

  display: block;
  text-align: center;
  background-color: rgba(0, 0, 0, 0.5);
}
#mozPrintCallback-shim[hidden] {
  display: none;
}
@media print {
  #mozPrintCallback-shim {
    display: none;
  }
}

#mozPrintCallback-shim .mozPrintCallback-dialog-box {
  display: inline-block;
  margin: -50px auto 0;
  position: relative;
  top: 45%;
  left: 0;
  min-width: 220px;
  max-width: 400px;

  padding: 9px;

  border: 1px solid hsla(0, 0%, 0%, .5);
  border-radius: 2px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);

  background-color: #474747;

  color: hsl(0, 0%, 85%);
  font-size: 16px;
  line-height: 20px;
}
#mozPrintCallback-shim .progress-row {
  clear: both;
  padding: 1em 0;
}
#mozPrintCallback-shim progress {
  width: 100%;
}
#mozPrintCallback-shim .relative-progress {
  clear: both;
  float: right;
}
#mozPrintCallback-shim .progress-actions {
  clear: both;
}
  </style>
  <div class="mozPrintCallback-dialog-box">
    <!-- TODO: Localise the following strings -->
    Preparing document for printing...
    <div class="progress-row">
      <progress value="0" max="100"></progress>
      <span class="relative-progress">0%</span>
    </div>
    <div class="progress-actions">
      <input type="button" value="Cancel" class="mozPrintCallback-cancel">
    </div>
  </div>
</div>