Javascript current TZ string (for ISO_8601)

tzsnippet.js

/**
 * This snipped generates the offset part of ISO_8601 datetime strings.
 * Useful for composed datetime strings as required for APIs complying RFC3339.
 */
var
  tz = (new Date()).getTimezoneOffset(),
  pad = function (v){
   var sv = Math.abs(parseInt(v, 10)).toString();
   return '00'.substr(sv.length) + sv;
  },
  tzstr = (tz<0?'+':'-') + pad(tz/60) + ':' + pad(tz%60);