var payload = new Uint8Array(NfcUtils.fromUTF8("\u0003mozilla.org")); // URL data, with a short record prefix 0x3 replacing http://
var ndefRecord ndefRecords = [new MozNDEFRecord(tnf, type, id, payload)];
var writereq = nfctag.writeNDEF([ndefRecord]ndefRecords);
writereq.onsuccess = function(e) {
console.log("Successfully wrote records to tag");