If we refer to the formal syntax: The / is the separation between background-position and background-size (this one being optional) so the correct syntax is: background: url(…) 100% 0/4% no-repeat; Where background-position:100% 0 and background-size:4% Note that background-size should always be specified with background-position when using shorthand syntax. You cannot specify the size without position … Read more
Although the syntax for vendor extensions is mentioned in the CSS3 Syntax module and introduced into the grammar to allow vendors to implement their own prefixes ignoring the standard, the actual vendor extensions themselves are not recognized as official CSS properties. This is not going to change, as they’re proprietary and specific to the vendors … Read more
(Theoretically) in HTML 4, <foo / (yes, with no > at all) means <foo> (which leads to <br /> meaning <br>> (i.e. <br>>) and <title/hello/ meaning <title>hello</title>). I use the term “theoretically” because this is an SGML rule that browsers did a very poor job of supporting. There was so little support (I only ever … Read more