全局发送头添

$(document).ajaxSend(function(event, jqxhr, settings) {
        jqxhr.setRequestHeader("Auth","http://xxx.com");
});

只处理指定页面

$(document).ajaxSend(function(event, jqxhr, settings) {
  if ( settings.url == "ajax/test.html" ) {
    $( ".log" ).text( "Triggered ajaxSend handler." );
  }
});