Describe the Techniques for Using Visualforce to Perform Actions and Partial Page Refresh. PLATFORM-DEVELOPER-II Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   A Visualforce page contains an actionRegion that wraps a command button and an input field. When the button is clicked, what is the effect of the actionRegion on the AJAX request?

   • AThe actionRegion prevents any server-side processing and only performs client-side validation.
   • BThe entire page is processed and refreshed, but only the actionRegion's contents are sent to the server.
   • CThe actionRegion ensures that all view state is excluded from the AJAX request to reduce payload size.
   • DOnly the components inside the actionRegion are processed and refreshed during the AJAX request.
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2. 17foundation · easy

   Which Visualforce component allows a non-action component, such as an input field, to trigger an AJAX request when its value changes?

   • AactionStatus
   • BactionPolling
   • CactionFunction
   • DactionSupport
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4. 18expert · hard

   A developer is optimizing a Visualforce page that has a large form with many input fields and a complex action method. The page currently uses a command button with a rerender attribute to refresh a small output panel. However, the page is slow because the entire form is being processed during the AJAX request. What should the developer do to improve performance?

   • AUse actionFunction instead of the command button.
   • BRemove the rerender attribute from the command button.
   • CWrap the output panel and the command button in an actionRegion.
   • DChange the command button to a commandLink.
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5. 19foundation · easy

   Which practice is recommended to optimize partial page refresh in Visualforce?

   • AUse multiple actionPolling components to keep all sections updated.
   • BUse actionRegion to limit the components processed during an AJAX request.
   • CAlways rerender the entire page to ensure all data is current.
   • DAvoid using actionRegion because it increases server load.
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6. 20application · medium

   A Visualforce page has an input field for a zip code. When the user enters a zip code and tabs out of the field, the page should automatically look up the city and state and update two output fields. The lookup should only process the zip code field. What should the developer do?

   • AUse a commandButton with a rerender attribute to the city and state output fields.
   • BUse actionFunction with a JavaScript onblur handler to call the controller.
   • CUse actionPolling on the input field with a rerender attribute to the city and state output fields.
   • DUse actionSupport on the input field with an event attribute of 'onblur', and set its rerender attribute to the city and state output fields.
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