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

Answer:

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” typically occurs when trying to set the value of a file input element using JavaScript.

File input elements in HTML are designed to allow users to select a file from their local filesystem. For security reasons, JavaScript is not allowed to set the value of a file input element to anything other than an empty string. This is to prevent malicious websites from pre-filling file inputs with fake or sensitive user data.

To illustrate this with an example, consider the following HTML code:

    
      <input type="file" id="myFileInput">
      <button onclick="setFileName()">Set File Name</button>
    
  

And JavaScript code:

    
      function setFileName() {
        var fileInput = document.getElementById('myFileInput');
        fileInput.value = 'example.txt'; // Attempt to set the file name
      }
    
  

When you click the “Set File Name” button, you will receive the error mentioned above in the console, indicating that setting the ‘value’ property of the file input is not allowed. Instead, you can only obtain the selected file using the file input’s files property or by listening to a change event on the input element.

    
      function handleFileChange() {
        var fileInput = document.getElementById('myFileInput');
        console.log(fileInput.files[0]?.name); // Access and log the selected file's name, if any
      }
      
      var fileInput = document.getElementById('myFileInput');
      fileInput.addEventListener('change', handleFileChange);