How can I get the current PDF page number from PDF.js iframe?

Question

I have the viewer hosted on my local webserver and the iframe points and loads up the pdf.

I then want to press a button that 'logs' the page number to a text file, I read this question and answer which seems to suggest you can use pdf.getPage to get the page number but how can i access the PDFJS when it is being ran from inside of the iframe?

Thank you.

Answer 1

var iFrame =  document.getElementById('iframe_id');
if ( iFrame.contentDocument ) {
    currentPageNum= iFrame.contentDocument.getElementById('pageNumber').value;
}
alert(currentPageNum);

This will access the iframe and then search the viewer.html for the element that contains the page number. All that needs doing now is to pass currentPageNum to the form.