printPage.js

/* Source: https://developer.mozilla.org/en-US/docs/Web/Guide/Printing#Print_an_external_page_without_opening_it */

function closePrint () {
  document.body.removeChild(this.__container__);
}

function setPrint () {
  this.contentWindow.__container__ = this;
  this.contentWindow.onbeforeunload = closePrint;
  this.contentWindow.onafterprint = closePrint;
  this.contentWindow.focus(); // Required for IE
  this.contentWindow.print();
}

function printPage (sURL) {
  var oHiddFrame = document.createElement("iframe");
  oHiddFrame.onload = setPrint;
  oHiddFrame.style.visibility = "hidden";
  oHiddFrame.style.position = "fixed";
  oHiddFrame.style.right = "0";
  oHiddFrame.style.bottom = "0";
  oHiddFrame.src = sURL;
  document.body.appendChild(oHiddFrame);
}