[news.eclipse.webtools] how to understand the non-standard tags in html

[Jus <lunjinyuan@xxxxxxx>]

Hi,

I saw some html tags:
        <f:view>
which is based on JSF.

I am wondering that tag f is not a standard tag of html, thus I cann't
find it at the reference from w3school:
        http://www.w3schools.com/tags/default.asp
then How could we use these tags? is it user defined? or these tags are
resoved by the browser? could I find the answer from the html specification:

http://www.w3.org/TR/REC-html40/cover.html#minitoc

Many thanks

Jing