Ajax Components

APEX:ACTIONREGION

An area of a Visualforce page that demarcates which components should be processed by the Force.com server when an AJAX request is generated. Only the components in the body of the <apex:actionRegion> are processed by the server, thereby increasing the performance of the page.

Note that an <apex:actionRegion> component only defines which components the server processes during a request—it does not define what area(s) of the page are re-rendered when the request completes. To control that behavior, use the rerender attribute on an <apex:actionSupport>, <apex:actionPoller>, <apex:commandButton>, <apex:commandLink>, <apex:tab>, or <apex:tabPanel> component.

APEX:ACTIONFUNCTION

A component that provides support for invoking controller action methods directly from JavaScript code using an AJAX request. An <apex:actionFunction> component must be a child of an <apex:form> component.

Unlike <apex:actionSupport>, which only provides support for invoking controller action methods from other Visualforce components, <apex:actionFunction> defines a new JavaScript function which can then be called from within a block of JavaScript code.

Note: Beginning with API version 23 you can't place <apex:actionFunction> inside an iteration component — <apex:pageBlockTable>, <apex:repeat>, and so on. Put the <apex:actionFunction> after the iteration component, and inside the iteration put a normal JavaScript function that calls it.

APEX:ACTIONPOLLER

A timer that sends an AJAX request to the server according to a time interval that you specify. Each request can result in a full or partial page update.

An <apex:actionPoller> must be within the region it acts upon. For example, to use an <apex:actionPoller> with an <apex:actionRegion>, the <apex:actionPoller> must be within the <apex:actionRegion>.

Considerations When Using <apex:actionPoller>

Action methods used by <apex:actionPoller> should be lightweight. It's a best practice to avoid performing DML, external service calls, and other resource-intensive operations in action methods called by an <apex:actionPoller>. Consider carefully the effect of your action method being called repeatedly by an <apex:actionPoller> at the interval you specify, especially if it's used on a page that will be widely distributed, or left open for long periods.

<apex:actionPoller> refreshes the connection regularly, keeping login sessions alive. A page with <apex:actionPoller> on it won't time out due to inactivity.

If an <apex:actionPoller> is ever re-rendered as the result of another action, it resets itself.

Avoid using this component with enhanced lists.

apex:actionStatus

A component that displays the status of an AJAX update request. An AJAX request can either be in progress or complete.

apex:actionSupport

A component that adds AJAX support to another component, allowing the component to be refreshed asynchronously by the server when a particular event occurs, such as a button click or mouseover.

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Description:

apex:actionRegion

An area of a Visualforce page that demarcates which components should be processed by the Force.com server when an AJAX request is generated. Only the components in the body of the <apex:actionRegion> are processed by the server, thereby increasing the performance of the page.

Note that an <apex:actionRegion> component only defines which components the server processes during a request—it does not define what area(s) of the page are re-rendered when the request completes. To control that behavior, use the rerender attribute on an <apex:actionSupport>, <apex:actionPoller>, <apex:commandButton>, <apex:commandLink>, <apex:tab>, or <apex:tabPanel> component.

apex:actionFunction

A component that provides support for invoking controller action methods directly from JavaScript code using an AJAX request. An <apex:actionFunction> component must be a child of an <apex:form> component.

Unlike <apex:actionSupport>, which only provides support for invoking controller action methods from other Visualforce components, <apex:actionFunction> defines a new JavaScript function which can then be called from within a block of JavaScript code.

Note: Beginning with API version 23 you can't place <apex:actionFunction> inside an iteration component — <apex:pageBlockTable>, <apex:repeat>, and so on. Put the <apex:actionFunction> after the iteration component, and inside the iteration put a normal JavaScript function that calls it.

apex:actionPoller

A timer that sends an AJAX request to the server according to a time interval that you specify. Each request can result in a full or partial page update.

An <apex:actionPoller> must be within the region it acts upon. For example, to use an <apex:actionPoller> with an <apex:actionRegion>, the <apex:actionPoller> must be within the <apex:actionRegion>.

Considerations When Using <apex:actionPoller>

Action methods used by <apex:actionPoller> should be lightweight. It's a best practice to avoid performing DML, external service calls, and other resource-intensive operations in action methods called by an <apex:actionPoller>. Consider carefully the effect of your action method being called repeatedly by an <apex:actionPoller> at the interval you specify, especially if it's used on a page that will be widely distributed, or left open for long periods.

<apex:actionPoller> refreshes the connection regularly, keeping login sessions alive. A page with <apex:actionPoller> on it won't time out due to inactivity.

If an <apex:actionPoller> is ever re-rendered as the result of another action, it resets itself.

Avoid using this component with enhanced lists.