The view-source URI scheme is used by some browsers to construct URLs that refer to a source display for a given resource.
For example, this URI would show the source of the page located at http://www.example.com view-source:http://www.example.com
On 25 May 2011 the 'view-source' URI scheme was officially registered with IANA per RFC 4395.
Browser support
Mozilla Firefox and Internet Explorer both supported the scheme, but support was dropped from Internet Explorer in Windows XP SP2 due to security problems. Firefox also suffered a similar security issue (by combining view-source and javascript URIs), but still supported it in Firefox 1.5 after being fixed. In 2009 a new discovered bug was fixed in Firefox 3.0.9.
References
View-source URI scheme Wikipedia(Text) CC BY-SA