浏览器以只读方式打开PDF

<button id="print" style="display:none;" class="toolbarButton print hiddenMediumView" title="Print" tabindex="33" data-l10n-id="print">
       <span data-l10n-id="print_label">Print</span>
</button>

 <button id="download" style="display:none;" class="toolbarButton download hiddenMediumView" title="Download" tabindex="34" data-l10n-id="download">
       <span data-l10n-id="download_label">Download</span>
</button>

<script>
document.addEventListener("keydown", function(e) {
    if (e.keyCode == 83 && (navigator.platform.match("Mac") ? e.metaKey : e.ctrlKey)) {
      e.preventDefault();
      e.stopPropagation();
    }
  }, false);
</script>