Can't get document.execCommand("copy") to work

Anki Desktop
1

I’m trying to use the document.execCommand(“copy”) method to get text onto the clipboard but it doesn’t work. The item is selected OK but never makes it to the clipboard. I got the code from a Stack Exchange answer:

// Create a dummy input to copy the string array inside it
  var dummy = document.createElement("input");

  // Add it to the document
  document.body.appendChild(dummy);

  // Set its ID
  dummy.setAttribute("id", "dummy_id");

  // Output the array into it
  document.getElementById("dummy_id").value=checkbx;

  // Select it
  dummy.select();

  // Copy its contents
  document.execCommand("copy");

  // Remove it as its not needed anymore
  document.body.removeChild(dummy);

I am using exactly the same code, except that I swapped out “chkbox” for a variable containing the textContent of an Anki field. If I put a timeout on the last line I can see that the input field does appear, that it contains the right text and that the text is selected - but the actual copying never happens.

Anyone know where the problem might be? I tried using a textarea instead of an input but it didn’t help.

2

Actually Anki has to do something very similar at one point: anki/TagEditor.svelte at 16fe18d033a8c80ec5f06a70455b99fa72f33821 · ankitects/anki · GitHub
You could check if that works for you.

It seems the main difference is that it uses textarea instead of input. (don’t forget to remove Typescript type annotations).

1 Like
3

Thanks. Substituting that exact code gives an error unless I put “document.” in front of “execCommand”. With that change the error goes away but the field still isn’t copied (actually it did work a couple of times in maybe 7 attempts, but so did an earlier version of the Stack Exchange code - I can’t get it to work consistently).

Should I be putting something other than “document.” in front of “execCommand”?

Otherwise, could it be to do with the variable type of content (in textarea.value=content)? I have tried content = String.raw{{Anki field}} and content = document.getElementById(“Id”).textContent.

4

If it only works sometimes, it seems to be some timing issue. Something else is stealing keyboard focus before the function is executed.

5

Thanks a lot - yes that does seem to be the problem. If I kill AutoHotkey it generally works, but still not every time, and anyway I need AHK running (in fact the whole reason I’m copying the data to the clipboard is to get it into AHK).

I can’t find a way of getting the script to wait until the window has focus. I tried adding textarea.addEventListener(“focus”, copyFunction), and that sort of works, but you have to click in the textarea to get the copy operation to execute. Is there a better way to delay it until the window has focus?