data = {/* POST body, as an key-value object */} var form = document.createElement("form"); form.setAttribute("method", "post"); form.setAttribute("action", url); form.setAttribute("target", "_blank") for(var key in data) { var hiddenField = document.createElement("input"); hiddenField.setAttribute("type", "hidden"); hiddenField.setAttribute("name", key); hiddenField.setAttribute("value", data[key]); form.appendChild(hiddenField); } document.body.appendChild(form); form.submit();