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">
