Bug 1529203 Comment 11 Edit History

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Original comment by
on 
> bz, is it possible for a Document object to be used with more than one global in its lifetime?

Yes, with document.open, which is exactly what's going on here.  A minimized testcase for this bug:

  <!DOCTYPE HTML>
  <iframe></iframe>
  <script>
    function doIt() {
      var doc = document.querySelector("iframe").contentDocument;
      doc.open();
      doc.write('<script>import("data:text/javascript,")</' + 'script>');
      doc.close();
    }
  </script>
  <button type="button" onclick="doIt()">
    Click this button, then wait a second and click it again.
  </button>

Even with bug 1523843 fixed, this is an issue for the moment, as this testcase shows:

  <!DOCTYPE HTML>
  <script>
    var win;
    function doIt() {
      if (!win) {
        win = window.open();
      }
      var doc = win.document;
      doc.open();
      doc.write('<script>import("data:text/javascript,")</' + 'script>');
      doc.close();
    }
  </script>
  <button type="button" onclick="doIt()">
    Click this button, then wait a second and click it again.
  </button>

Bug 1489308 will fix the issue by removing the "single document with multiple globals" situation.  But that's not landed yet, so we need a different fix for Firefox 66, right?
Revision 1 by
on 
> bz, is it possible for a Document object to be used with more than one global in its lifetime?

Yes, with document.open, which is exactly what's going on here.  A minimized testcase for this bug:
```
  <!DOCTYPE HTML>
  <iframe></iframe>
  <script>
    function doIt() {
      var doc = document.querySelector("iframe").contentDocument;
      doc.open();
      doc.write('<script>import("data:text/javascript,")</' + 'script>');
      doc.close();
    }
  </script>
  <button type="button" onclick="doIt()">
    Click this button, then wait a second and click it again.
  </button>
```
Even with bug 1523843 fixed, this is an issue for the moment, as this testcase shows:
```
  <!DOCTYPE HTML>
  <script>
    var win;
    function doIt() {
      if (!win) {
        win = window.open();
      }
      var doc = win.document;
      doc.open();
      doc.write('<script>import("data:text/javascript,")</' + 'script>');
      doc.close();
    }
  </script>
  <button type="button" onclick="doIt()">
    Click this button, then wait a second and click it again.
  </button>
```
Bug 1489308 will fix the issue by removing the "single document with multiple globals" situation.  But that's not landed yet, so we need a different fix for Firefox 66, right?

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