Visualforce Developer Guide

Introducing Visualforce
Tools for Visualforce Development
Getting a Quick Start with Visualforce
Customizing the Appearance and Output of Visualforce Pages
Standard Controllers
Standard List Controllers
Custom Controllers and Controller Extensions
Advanced Examples
Override Buttons, Links, and Tabs with Visualforce
Using Static Resources
Creating and Using Custom Components
Dynamic Visualforce Bindings
Dynamic Visualforce Components
Integrate Email with Visualforce
Visualforce Charting
Creating Maps with Visualforce
Render Flows with Visualforce
Templating with Visualforce
Developing Salesforce Apps with Visualforce
Adding Visualforce to a Salesforce AppExchange App
Using JavaScript in Visualforce Pages
Communicating Across the DOM with Lightning Message Service
Visualforce Best Practices
Standard Visualforce Component Reference
Appendices
Global Variables, Functions, and Expression Operators
Global Variables
$Action
$Api
$Asset
$Cache.Org
$Cache.Session
$Component
$ComponentLabel
$CurrentPage
$FieldSet
$Label
$Label.Site
$MessageChannel
$Network
$ObjectType
$Organization
$Page
$Permission
$Profile
$Resource
$SControl
$Setup
$Site
$System.OriginDateTime
$User
$User.UITheme and $User.UIThemeDisplayed
$UserRole
Functions
Expression Operators
Security Tips for Apex and Visualforce Development
Apex Classes Used in Visualforce Controllers
Execution Governors and Limits
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$Component

A global merge field type to use when referencing a Visualforce component.

Usage

Each component in a Visualforce page has its own Id attribute. When the page is rendered, this attribute is used to generate the Document Object Model (DOM) ID. Use $Component.Path.to.Id in JavaScript to reference a specific component on a page, where Path.to.Id is a component hierarchy specifier for the component being referenced.

Example

The following JavaScript method references a component named msgpost in a Visualforce page:
The page markup that follows shows the <apex:outputText> component to which msgpost refers:
If your component is nested, you might need to use a more complete component path specifier. For example, if your page looks like this:
Then you can refer to the component in a function like this: