The JS code that will add an input file button to ChatGPT. You can add a file and feed it into ChatGPT

chatGPT_input

// Create the file input element
var fileInput = document.createElement('input');
fileInput.type = 'file';
fileInput.id = 'fileInput';
fileInput.style.display = 'none'; // Hide the file input
fileInput.accept = '.txt'; // Accept only .txt files

// Create the button element
var button = document.createElement('button');
button.textContent = 'Upload txt file';
button.style.display = 'block'; // Make the button block-level to appear on its own line

// Attach event listener to button
button.addEventListener('click', function() {
    // Trigger the file input click
    fileInput.click();
});

// Attach event listener to file input
fileInput.addEventListener('change', async function() {
    if (this.files && this.files[0]) {
        var myFile = this.files[0];
        var reader = new FileReader();
        
        reader.addEventListener('load', async function(e) {
            var fileContent = e.target.result;
            
            // Split the file content into chunks
            var chunks = chunkSubstr(fileContent, 15000);
            
            // For each chunk, simulate text input and submission
            for (var i = 0; i < chunks.length; i++) {
                var chunk = chunks[i];
                
                // Insert chunk into the textarea
                var textArea = document.getElementById('prompt-textarea');
                textArea.value = chunk;
                
                // Simulate a 'change' event to make sure React picks up the change
                var event = new Event('input', { bubbles: true });
                textArea.dispatchEvent(event);
                
                // This should ideally "submit" the text, but it might not work
                // due to security measures put in place by many websites
                var sendButton = textArea.parentNode.querySelector('button');
                if (sendButton) {
                    sendButton.click();
                }
                
                // Sleep for a second (or more if needed) to ensure previous message was processed
                await sleep(1000);
            }
        });
        
        reader.readAsText(myFile);
    }
});

// Insert the button and file input after the textarea
var textArea = document.getElementById('prompt-textarea');
textArea.insertAdjacentElement('afterend', button);
textArea.insertAdjacentElement('afterend', fileInput);

// Helper function to sleep for a specified duration
function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

// Helper function to split string into chunks
function chunkSubstr(str, size) {
  const numChunks = Math.ceil(str.length / size);
  const chunks = new Array(numChunks);

  for(let i = 0, o = 0; i < numChunks; ++i, o += size) {
    chunks[i] = str.substr(o, size);
  }

  return chunks;
}