1. jQuery.ajaxSetup ([options]), set the global AJAX default option.
See parameter 'jQuery.ajax (url, [settings])' instructions.
2. jQuery.ajax (url, [settings]), the remote loading HTTP request data.
jQuery underlying AJAX implementation. $ .Ajax () returns the XMLHttpRequest object that it creates. In most cases you do not need to directly operate the function, unless you do not need to operate frequently used options to get more flexibility.
In the simplest case, $. Ajax () can be used directly without any parameters.
All options are available through $ .ajaxSetup () function to global settings.