The "async" parameter specifies whether the request should be handled asynchronously or not.

The "async" parameter specifies whether the request should be handled asynchronously or not. "true" means that the script processing carries on after the send() method without waiting for a response, and "false" means that the script waits for a response before continuing script processing.

• The "async" parameter specifies whether the request should be handled asynchronously or not.