http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 there is no difference in HTML between quotes HTML 4.01, section 3.2.2 HTML 3-Spezifikation boolean attributes W3C http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 On SGML and HTML - W3C W3C http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 boolean attribute the relationship between SGML and HTML http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 the specification http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.1 HTML4 spec http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4 w3.org/TR/html4/intro/sgmltut.html#didx-attribute mandatory in this case http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 there is no difference in HTML between quotes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 HTML 3-Spezifikation http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 boolean attributes http://www.w3.org/TR/html4/intro/sgmltut.html W3C http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2 boolean attribute http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 w3.org/TR/html4/intro/sgmltut.html#didx-attribute w3.org/TR/html4/intro/sgmltut.html#didx-attribute mandatory in this case http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 W3C - SGML and HTML DTD http://www.w3.org/TR/html4/intro/sgmltut.html#attributes boolean attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 HTML reference manual says mandatory in this case On SGML and HTML: Attributes not in HTML http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 check out the spec http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 says http://www.w3.org/TR/html4/intro/sgmltut.html HTML comment tags W3C W3C http://w3.org/TR/html4/intro/sgmltut.html there is no difference in HTML between quotes On SGML and HTML: Attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 On SGML and HTML: Attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 spec http://www.w3.org/TR/html4/intro/sgmltut.html#idx-HTML W3C empty elements http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 On SGML and HTML spec boolean attribute http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 HTML element boolean attribute W3C http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.4.2 On SGML and HTML: Attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.1 boolean attribute boolean attribute http://w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 should be quoted HTML Comments http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 Boolean attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2 SGML comments boolean attribute http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.1 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 W3C http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 spec defines W3C mandatory in this case http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2 mandatory in this case http://w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 On SGML and HTML: Attributes w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.4 HTML 4 http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 empty content model boolean attributes http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.1 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 A common error ... there is no difference in HTML between quotes character reference http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 On SGML and HTML: Attributes a valid HTML4 comment HTML allows single or double quotes HTML element spec http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 On SGML and HTML: Attributes HTML Comments http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 http://www.w3.org/TR/html4/intro/sgmltut.html http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.2 HTML element http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.3.3 HTML 4.01, section 3.2.2 On SGML and HTML: Attributes conforming to HTML4 http://www.w3.org/TR/html4/intro/sgmltut.html#h-3.2.1 mandatory in this case