Using reRender where a VF component (that does JS remoting) exists causes a JS error in the browser
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Using reRender where a VF component (that does JS remoting) exists causes a JS error in the browser

VisualForce , Spring 14

Last updated 2022-02-10 ·Reference W-2122841 ·Reported By 2 users

Fixed - Spring '14

VF components that perform Javascript remoting are throwing the following Javascript error in browser console when being re-rendered on a VF page:

Visualforce Remoting: Unable to create method '[<insert function name>]': already exists on object '[<insert apex class/object name>]'

This error only occurs when the VF component (that does the Javascript remoting) is part of a rerendered section on a VF page.

Implications: due to this Javascript error, all subsequent Javascript processing on the browser side stops after this error. The actual Javascript remoting call still works, but when this error comes, other javascript codes that were expected to run stop running as the browser sees this error.

The following simplified code was created to simulate this error in our own spring and winter orgs.

Essentially re-rendering part of a visual force page that contains a component that does Javascript remoting will result in the error:

[JS Remoting APEX Controller]
global with sharing class RemoteActionController{

public RemoteActionController(ApexPages.StandardController controller) {}
public RemoteActionController() {}

// Main function which returns result
global static String doRemote(String text) {
return text + '_processed';

[VF Remoting componant]
<apex:component controller="RemoteActionController" selfClosing="true">


function callRemote(){
Visualforce.remoting.Manager.invokeAction('{!$RemoteAction.RemoteActionController.doRemote}', 'TestDataParam',
function(result, event) {
escape: false

<apex:outputPanel >
<apex:outputLabel value="TEST: " rendered="true}"/>
<apex:outputPanel >
<button onclick="callRemote();">
Click Me


[VF Test Page Controller]
public class AccountRemoteTestController {

public AccountRemoteTestController (ApexPages.StandardController controller) {
this.showRemoteTester = false;
public AccountRemoteTestController () {
this.showRemoteTester = false;

public boolean showRemoteTester {get; set;}

public PageReference flipShowRemoteTester() {
this.showRemoteTester = true;

return null;


[VF Test Page]
<apex:page standardController="Account" extensions="AccountRemoteTestController ">
<apex:outputPanel id="buttonPanel">
<apex:commandButton id="commanBtn" oncomplete="alert('{!showRemoteTester}');" action="{!flipShowRemoteTester}" value="showComponent" reRender="remoteCompPanel"/>

<apex:outputPanel id="remoteCompPanel" >
<c:RemotingComponant />

No workaround exists at this point.

Is it Fixed?

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