Failed to set the ‘value’ property on ‘htmlinputelement’: this input element accepts a filename, which may only be programmatically set to the empty string.

When you encounter the error message “Failed to set the ‘value’ property on ‘HTMLInputElement’: This input element accepts a filename, which may only be programmatically set to the empty string”, it typically means that you are trying to set the value of an input element of type “file” to something other than an empty string.

The input element of type “file” is used to create a file upload control, allowing users to select files from their local system. The value of this type of input is read-only for security reasons, meaning you cannot directly set it using JavaScript or other client-side code. The value can only be changed by user interaction, that is, when the user selects a file using the file browser dialog.

Here’s an example that demonstrates the issue:

<input type="file" id="myFileInput" />

<script>
  document.getElementById("myFileInput").value = "example.txt"; // Trying to set the value programmatically
</script>

In this example, we are trying to set the value of the “myFileInput” element to “example.txt” using JavaScript, but it will result in the error mentioned above. As mentioned earlier, you can only set the value of a file input element to an empty string programmatically.

If you want to preselect a file or clear the selection programmatically, you have to reset the entire input element by cloning and replacing it with a new one. Here’s how you can do it:

<input type="file" id="myFileInput" />

<script>
  var oldInput = document.getElementById("myFileInput");
  var newInput = oldInput.cloneNode(true);

  oldInput.parentNode.replaceChild(newInput, oldInput);

  newInput.value = ""; // Programmatically setting the value to an empty string
</script>

In this updated example, we create a new input element using the cloneNode method and replace the old input element with the new one. Now, we can set the value of the new input element to an empty string, effectively clearing any previously selected file.