Reading a local file from an HTML page

Giganews Newsgroups
Subject: Reading a local file from an HTML page
Posted by:  dr.j.r.stockt…@gmail.com
Date: Thu, 2 Apr 2020

I currently have, in a HTML page

<iframe class=FYL ID=Iframe style="width:99%; height:270px;">
</iframe>

Fram = document.getElementById("Iframe")

function DiryToIframe(Diry) {
  Fram.onload = TimeOut ? DummyF : ReadDiryFromFram
  Fram.src = Diry
  if (TimeOut) setTimeout(ReadDiryFromFram, TimeOut)
  }

and that function call would, in several browsers, put the
contents of the file given by Diry, on the same computer, into
the above iframe element, and I could then do

  var DIR = Fram.contentDocument.body
  DIR = DIR.textContent || DIR.innerText // Is latter needed? Yes, IE8

and the variable DIR would then contain the contents of file
Diry.

That now only(?) works in Internet Explorer.

How do I set about doing that in all up-to-date browsers, disregarding
IE11 and current Edge, but including the imminent new Edge?

The whole thing must operate without user intervention, browsing
for a file name, even if the full name were known exactly, would
be intolerable.

Currently, I would be sufficiently sure that the file Diry exists;
but subsequently I will want to know whether the file does exist
before/after attempting to read it.

--
  (c) John Stockton, near London, UK.  Using Google Groups.          |
Mail: J.R.""""""""@physics.org - or as Reply-To, if any.            |

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