List of <p:ajax> events

Schedule provides various ajax behavior events to respond user actions.

• "dateSelect" org.primefaces.event.SelectEvent When a date is selected.
• "eventSelect" org.primefaces.event.SelectEvent When an event is selected.
• "eventMove" org.primefaces.event.ScheduleEntryMoveEvent When an event is moved.
• "eventResize" org.primefaces.event.ScheduleEntryResizeEvent When an event is resized.
• "viewChange" org.primefaces.event.SelectEvent When a view is changed.
• "toggleSelect" org.primefaces.event.ToggleSelectEvent When toggle all checkbox changes
• "expand" org.primefaces.event.NodeExpandEvent When a node is expanded.
• "collapse" org.primefaces.event.NodeCollapseEvent When a node is collapsed.
• "select" org.primefaces.event.NodeSelectEvent When a node is selected.-
• "collapse" org.primefaces.event.NodeUnselectEvent When a node is unselected
• "expand org.primefaces.event.NodeExpandEvent When a node is expanded.
• "unselect" org.primefaces.event.NodeUnselectEvent When a node is unselected.
• "colResize" org.primefaces.event.ColumnResizeEvent When a column is resized
• "page" org.primefaces.event.data.PageEvent On pagination.
• "sort" org.primefaces.event.data.SortEvent When a column is sorted.
• "filter" org.primefaces.event.data.FilterEvent On filtering.
• "rowSelect" org.primefaces.event.SelectEvent When a row is being selected.
• "rowUnselect" org.primefaces.event.UnselectEvent When a row is being unselected.
• "rowEdit" org.primefaces.event.RowEditEvent When a row is edited.
• "rowEditInit" org.primefaces.event.RowEditEvent When a row switches to edit mode
• "rowEditCancel" org.primefaces.event.RowEditEvent When row edit is cancelled.
• "colResize" org.primefaces.event.ColumnResizeEvent When a column is being selected.
• "toggleSelect" org.primefaces.event.ToggleSelectEvent When header checkbox is toggled.
• "colReorder" - When columns are reordered.
• "rowSelectRadio" org.primefaces.event.SelectEvent Row selection with radio.
• "rowSelectCheckbox" org.primefaces.event.SelectEvent Row selection with checkbox.
• "rowUnselectCheckbox" org.primefaces.event.UnselectEvent Row unselection with checkbox.
• "rowDblselect" org.primefaces.event.SelectEvent Row selection with double click.
• "rowToggle" org.primefaces.event.ToggleEvent Row expand or collapse.
• "contextMenu" org.primefaces.event.SelectEvent ContextMenu display.
• "cellEdit" org.primefaces.event.CellEditEvent When a cell is edited.
• "rowReorder" org.primefaces.event.ReorderEvent On row reorder.

there is more in here https://www.primefaces.org/docs/guide/primefaces_user_guide_5_0.pdf

As the list of possible events is not tied to p:ajax itself but to the component it is used with, you'll have to ask the component for which ajax events it supports.

There are multiple ways to determine the ajax events for a given component:

1) Ask the component in xhtml:

You can output the list directly in xhtml by binding that component to a request scoped variable and printing the eventNames property:

<p:autoComplete binding="#{ac}"></p:autoComplete>
<h:outputText value="#{ac.eventNames}" />

This outputs

[blur, change, valueChange, click, dblclick, focus, keydown, keypress, keyup,
 mousedown, mousemove, mouseout, mouseover, mouseup, select, itemSelect,
 itemUnselect, query, moreText, clear]

2) Ask the component in java code:

Figure out the component implementation class and invoke its' implementation of javax.faces.component.UIComponentBase.getEventNames() method:

import javax.faces.component.UIComponentBase;

public class SomeTest {

    public static void main(String[] args) {
        dumpEvents(new org.primefaces.component.inputtext.InputText());
        dumpEvents(new org.primefaces.component.autocomplete.AutoComplete());
        dumpEvents(new org.primefaces.component.datatable.DataTable());
    }

    private static void dumpEvents(UIComponentBase comp) {
        System.out.println(
                comp + ":\n\tdefaultEvent: " + comp.getDefaultEventName() + ";\n\tEvents: " + comp.getEventNames());
    }

}

This outputs:

org.primefaces.component.inputtext.InputText@239963d8:
    defaultEvent: valueChange;
    Events: [blur, change, valueChange, click, dblclick, focus, keydown, keypress, keyup, mousedown, mousemove, mouseout, mouseover, mouseup, select]
org.primefaces.component.autocomplete.AutoComplete@72d818d1:
    defaultEvent: valueChange;
    Events: [blur, change, valueChange, click, dblclick, focus, keydown, keypress, keyup, mousedown, mousemove, mouseout, mouseover, mouseup, select, itemSelect, itemUnselect, query, moreText, clear]
org.primefaces.component.datatable.DataTable@614ddd49:
    defaultEvent: null;
    Events: [rowUnselect, colReorder, tap, rowEditInit, toggleSelect, cellEditInit, sort, rowToggle, cellEdit, rowSelectRadio, filter, cellEditCancel, rowSelect, contextMenu, taphold, rowReorder, colResize, rowUnselectCheckbox, rowDblselect, rowEdit, page, rowEditCancel, virtualScroll, rowSelectCheckbox]

3) 'rtfm' ;-)

Best option is to look into the documentation of the particular component in use as hopefully provided by the component developers, not limited to PrimeFaces btw. (p:ajax can be attached to any component providing ajax behaviors).

The advantage over previous suggestions is that the documentation not only provides the event names, but also enhanced description of the event potentially enriched with an event type class that can be caught by a listener.

For example the org.primefaces.event.SelectEvent in case of

<p:ajax event="itemSelect" listener="#{anyBean.onItemSelect}"/>

and listener method signature public void onItemSelect(SelectEvent) provides additional event contextual data.

Where there is no explicit list of ajax events on a compoment in the PrimeFaces documentation, the list of on* javascript callbacks can be used as events by removing the 'on' and using the remainder as an event name. The other answers in this question provides help on these plain dom events too.

Here's what I found during debug.