How to Print PDFs Directly from JavaScript using an Iframe?

Printing PDFs Directly from JavaScript Uncovered

Web applications often involve the need to provide users with the option to download or print PDFs. Traditionally, users would have to open the PDF in a viewer before initiating the print process. However, advancements in JavaScript have brought forth the possibility of directly opening the print dialog for a PDF without requiring any user interaction with the document itself.

One approach for achieving this involves downloading the PDF into a hidden iframe, then triggering the print request using JavaScript. This workflow can be implemented as follows:

• Embed the PDF in a hidden iframe: Utilize the tag to embed the PDF within the HTML document. Ensure that the iframe remains hidden from the user's view.
• Detect PDF load completion: Employ a loop or timer to continuously check if the PDF has finished loading within the iframe. This step is crucial as attempting to print an unloaded PDF will result in an error.
• Initiate printing: Once the PDF is confirmed to have finished loading, invoke the .print() method on the iframe's embed element. This action will open the print dialog, allowing the user to select the desired printer and initiate the printing process.

Example code to print a PDF embedded in an iframe:

<code class="javascript">function printPDF() {
  // Create a hidden iframe
  const iframe = document.createElement('iframe');
  iframe.style.display = 'none';
  document.body.appendChild(iframe);

  // Load the PDF into the iframe
  iframe.src = 'path_to_pdf_document.pdf';

  // Wait for the PDF to load
  const printInterval = setInterval(() => {
    if (iframe.contentWindow.document.readyState === 'complete') {
      clearInterval(printInterval);
      iframe.contentWindow.print();
      document.body.removeChild(iframe);
    }
  }, 100);
}</code>

By implementing this approach, you can provide users with a seamless printing experience without requiring them to manually open the PDF or a separate PDF viewer before initiating the print process. It's important to note that this solution may not be supported by all browsers and versions.

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