Web programming frameworks generating "//" for links

Question

Recently, I noticed that many web programming frameworks are used //in front of some generated links hrefandsrc

//example from twitter.com
<a href="//support.twitter.com">Help</a>

Is this just a shortcut to http/ httpsor something else?

Does anyone know where this method got its start, and if there is a browser support matrix that confirms / describes the behavior of the host //?

Answer 1

This protocol is the relative URL that Paul Ireland best describes; http://paulirish.com/2010/the-protocol-relative-url/

, URL- (, "//" "http://" "https://" ), " , " msgstr " Internet Explorer (, , ). .css , "http://" "https://" "//".