docs: function sendMessage() {
      var cache = [];
      var args = [].slice.call(arguments);
  
      // Safe stringifying of cyclical JSON
      function decycle(key, val) {
        if (typeof val === 'object' && val !== null) {
          if (cache.indexOf(val) >= 0) return;
          cache.push(val);
        }
        return val;
      }
  
      alert(JSON.stringify(args, decycle));
    }