HTML Email Doctype
What’s the best HTML Email Doctype?
Since there is no development standard for HTML email, the best document type for building HTML Email Templates is the doctype which allows your email template design to render properly on all testable email clients.
While the latest doctype for the web is HTML5, some of the largest email service providers and testing services still recommend XHTML 1.0 Transitional as the preferred html email doctype.
After testing email template code on the 80+ email clients through Email on Acid I can confirm that the XHTML 1.0 Transitional Doctype allows for proper rending on all email clients. Here is the complete document type HTML with the xml namespace link included for the xlmns attribute in addition to language english:
<!DOCTYPE htmlPUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
..continue to the next lesson: HTML Email Metadata.