XHTML Validation

From http://www.w3schools.com (Copyright Refsnes Data)

# XHTML Validation

An XHTML document can be validated with W3C's validator.

## Validate XHTML With A DTD

Before an XHTML file can be validated, a correct DTD must be added as the first line of the file.

The Strict DTD includes elements and attributes that have not been deprecated or do not appear in framesets:

    !DOCTYPE html PUBLIC
    "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"

The Transitional DTD includes everything in the strict DTD plus deprecated elements and attributes:

    !DOCTYPE html PUBLIC
    "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"

The Frameset DTD includes everything in the transitional DTD plus frames as well:

    !DOCTYPE html PUBLIC
    "-//W3C//DTD XHTML 1.0 Frameset//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd"

## Validate Your XHTML With The W3C Validator

Input a web address in the box below:

From http://www.w3schools.com (Copyright Refsnes Data)