Clear clipboard to prohibit unauthorised copying, insert message?

Question

Is it possible to write your own message into the clipboard when copying website data using ctrl+c? I've found some Javascript that clears the clipboard - would be interesting to know if there's something that would write to it as well, i.e. replace the text in the clipboard with something like 'Please use the print edition of our website'.

  function clearData() {
    window.clipboardData.setData('text', '')
  }

  function cldata() {
    if (clipboardData) {
      clipboardData.clearData();
    }
  }
  setInterval("cldata()", 1000);

<body ondragstart="return false;" onselectstart="return false;" oncontextmenu="return false;" onload="clearData();" onblur="clearData();">

  <h1>Example text</h1>
<input type="text">

Websites that attempt to subvert standard browser functionality are really irritating. Please don't! — Oliver Charlesworth, May 25 '13 at 10:44
A user can still save the page locally as HTML, then copy text from that anyway... — Qantas 94 Heavy, May 25 '13 at 10:49

score 3 · Accepted Answer · edited May 23 '17 at 10:33

3

You can't do it purely through JavaScript.

JavaScript editing of the clipboard is considered a security vulnerability (and there is much more discussion on this).

You could do it through hacks that uses Flash for clipboard access interacting with JavaScript.

edited May 23 '17 at 10:33

Community

1
1

answered May 25 '13 at 16:32

Justin

471
2
8

But it is possible to write to the clipboard using the [async clipboard API](https://stackoverflow.com/a/30810322/975097). – Anderson Green Dec 11 '21 at 18:37

score 1 · Answer 2 · answered Aug 11 '21 at 05:08

1

You cannot clear clipboard data since there is no function for that.

Best way to remove it is to assign null values.

ie

navigator.clipboard.writeText("");

answered Aug 11 '21 at 05:08

Rajesh Kumar Karthigesan

31
1
4

score 0 · Answer 3 · answered Sep 26 '18 at 19:37

You could place the following:

$( document ).ready(function() {
    if (event.ctrlKey && event.keyCode == 67) {
        var inputFieldClear = document.createElement("input");
        inputFieldClear.setAttribute("value", "Insert Default Value Here");
        document.body.appendChild(inputFieldClear);
        inputFieldClear.select();
        document.execCommand('copy');
        inputFieldClear.remove();
        console.log("Attempting to Alter Clipboard")
}});

That would work in something like TamperMonkey - not sure if it could be incorporated into the sites source or not.

Hope it helps! :)

score 0 · Answer 4 · answered Jan 06 '21 at 12:44

0

  function clearData() {
    window.clipboardData.setData('text', '')
  }

  function cldata() {
    if (clipboardData) {
      clipboardData.clearData();
    }
  }
  setInterval("cldata()", 1000);

<body ondragstart="return false;" onselectstart="return false;" oncontextmenu="return false;" onload="clearData();" onblur="clearData();">

  <h1>Example text</h1>
<input type="text">

answered Jan 06 '21 at 12:44

M T

1

Welcome to SO. Please explain your answer for future readers. – Nik Jan 06 '21 at 13:02
Ouch, I haven't seen anyone in the last 6-8 years passing a string of code to `setInterval`. I hope you know that it's not recommended. – Zsolt Meszaros Jan 06 '21 at 13:45

score 0 · Answer 5 · answered Jan 05 '22 at 23:41

You can't clear a user's clipboard history. But,

You can replace their clipboard with something else like

navigator.clipboard.writeText(" ");

Or you can make a script that whenever they try to copy something it stops it.

document.addEventListener('copy', function(e){
    e.preventDefault();
})

score -1 · Answer 6 · edited May 23 '17 at 12:03

-1

Yes, you can. The basic trick is that you detect when a user holds down Control, and select a different piece of text on the page.

edited May 23 '17 at 12:03

Community

1
1

answered Apr 15 '14 at 18:03

James_pic

3,240
19
24

Clear clipboard to prohibit unauthorised copying, insert message?

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