The standard version of XHTML, version 1.0, is just a rewrite of HTML 4.0 in XML. You can find the W3C recommendation for XHTML 1.0 at www.w3.org/TR/xhtml1. Essentially, it's just a set of DTDs that provide validity checks for documents that are supposed to mimic HTML 4.0 (actually HTML 4.01). The W3C has created several DTDs for HTML 4.0, and the XHTML DTDs are based on those, translated into straight XML. As with HTML 4.0, XHTML 1.0 has three versions, which correspond to three DTDs here:
Here are the actual <!DOCTYPE> elements you should use in XHTML for these various DTDsstrict, transitional, and framesetincluding the URIs for these DTDs: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd"> I'm giving the DTDs' uniform resource indicators (URIs) here, so you can copy them and cache a local copy if you want for faster access. For example, if you place the DTD files in a directory named DTD in your Web site, your <!DOCTYPE> elements might look more like this: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd"> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "DTD/xhtml1-frameset.dtd"> If you cache these DTDs locally, there should be less of a bottleneck when XHTML becomes very popular and users try to download your documents. |