!DOCTYPE
<!DOCTYPE>Specifies the DTD the document corresponds to.
Different versions may be used depending on the level of compatibility the author wishes to indicate. In the examples below, the first indicates compatibility with the HTML 3.2 DTD; the second indicates a strict adherence to the HTML 4.0 DTD.
Examples
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Strict//EN">
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Strict//EN">