The  function is a shortcut function for .

//ajax shortcut    ab: function(cfg, ext) {        return PrimeFaces.ajax.AjaxRequest(cfg, ext);    }

The PrimeFaces.ajax.AjaxRequest can be asynchronous or synchronous. The  uses the , which handles all send, process, response, and update.

PrimeFaces.ajax.AjaxRequest = function(cfg, ext) {    cfg.ext = ext;    if(cfg.async) {        return PrimeFaces.ajax.AjaxUtils.send(cfg);    }    else {        return PrimeFaces.ajax.Queue.offer(cfg);    }}

Passing a cfg (configuration) object to the , this cfg object has:

• cfg.global: a boolean value used to trigger  if it's a true.
• cfg.onstart: to be called when the request is to be send.
• cfg.async: a boolean value, where if this call is asynchronous or not.
• cfg.source: can be a client id or an element defined by this keyword
• cfg.formId: if an explicit form is defined, or it would look into a parent source
• cfg.resetValues
• cfg.ignoreAutoUpdate
• cfg.fragmentId: used for the process of the components
• cfg.fragmentUpdate
• cfg.event: behaviour event, like click or change
• cfg.params: request params
• cfg.partialSubmit: if partial submit is enabled, there are components to process partially
• cfg.onerror: to be called when the request had an error status.
• cfg.onsuccess: to be called when the request had a success status.
• cfg.oncomplete: to be called when the request is completed.

Note: I came up with this explanation based on my understanding of the source code.

Also you can refer to this , might be helpful.

http://stackoverflow.com/questions/23031582/primefaces-ab-function