问题 I have a PDFTron webviewer which I use to render a pdf form. I need to extract the form xml from the webviewer when user click on external save button. I tried var am = readerControl.docViewer.getAnnotationManager(); var xfdfString = am.exportAnnotations(); $.ajax({ type: 'POST', url: readerControl.serverUrl + '?did=' + readerControl.docId, data: xfdfString, success: function(data) { // Annotations were successfully uploaded to server }, error: function(jqXHR, textStatus, errorThrown) {