Visualforce Developer’s Guide

Introducing Visualforce
Tools for Visualforce Development
Getting a Quick Start with Visualforce
Customizing the Appearance and Output of Visualforce Pages
Styling Visualforce Pages
HTML Comments and IE Conditional Comments
HTML Tags Added or Modified by Visualforce
Using a Custom Doctype
Using a Custom ContentType
Setting Custom HTML Attributes on Visualforce Components
Offline Caching Using the HTML5 manifest Attribute
Render a Visualforce Page as a PDF File
Standard Controllers
Standard List Controllers
Custom Controllers and Controller Extensions
Advanced Examples
Overriding Buttons, Links, and Tabs with Visualforce
Using Static Resources
Creating and Using Custom Components
Dynamic Visualforce Bindings
Dynamic Visualforce Components
Integrating Email with Visualforce
Visualforce Charting
Creating Maps with Visualforce
Render Flows with Visualforce
Templating with Visualforce
Developing for Mobile Devices
Adding Visualforce to a Force.com AppExchange App
Using JavaScript in Visualforce Pages
Best Practices
Standard Component Reference
Appendices
Glossary
PDF

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Using a Custom Doctype

You can specify a different “doctype” (document type, or DTD) for a Visualforce page by using the docType attribute on the <apex:page> tag. This changes the doctype declaration at the beginning of the page. This is particularly useful if you’re working with HTML5, and might also allow you to address browser compatibility issues.

By default, Visualforce pages are served with a doctype of HTML 4.01 Transitional. Specifically, pages begin with this doctype declaration:

1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

You can specify a different doctype for a Visualforce page by using the docType attribute on the <apex:page> tag.

The docType attribute takes a string representing the document type. The format of the string is:

1<doctype>-<version>[-<variant>]

where

  • doctype is either html or xhtml
  • version is a decimal version number valid for the doctype
  • variant, if included, is:
    • strict, transitional, or frameset for all html document types and the xhmtl-1.0 document type, or
    • <blank> or basic for the xhmtl-1.1 document type

If an invalid document type is specified, the default doctype is used. For more information about valid HTML doctypes, see the list at the W3C website.

In API 28.0 and greater, the scope of how the docType is determined for a page depends on the entire page hierarchy, not just the main page. When pages are added to the main page using the <apex:include> tag, if any page in the hierarchy is set to docType="html-5.0", the entire page hierarchy is rendered in that mode.

Note

Custom Doctype Example

To create a Visualforce page with an XHTML 1.0 Strict document type, use the docType attribute on the <apex:page> tag, and specify a value of xhtml-1.0-strict:

1<apex:page docType="xhtml-1.0-strict" title="Strictly XHTML" 
2    showHeader="false" sidebar="false">
3    <h1>This is Strict XHTML!</h1>
4    <p>
5        Remember to close your tags correctly:<br/>
6        <apex:image url="/img/icon-person.gif" alt="Person icon"/>
7    </p>
8</apex:page>

Visualforce doesn’t alter markup generated by components to match the doctype, nor the markup for standard Salesforce elements such as the header and sidebar. Salesforce elements are valid for most doctypes and function properly with any doctype, but if you choose a strict doctype and wish to pass an HTML validation test, you might need to suppress or replace the standard Salesforce elements.

Note