A ruby annotation:
<ruby> 漢 <rt><rp>(</rp><rp>)</rp></rt> </ruby>
Internet Explorer 9+, Firefox, Opera, Chrome and Safari support <rp> tag.
Note: 8 and earlier versions of Internet Explorer do not support the <rp> tag.
<Rp> tag is used in ruby annotations to define the content browser does not support the ruby element is displayed.
ruby annotation is Chinese phonetic or characters.
In East Asia used to display the pronunciation of East Asian characters.
And <ruby> and <rt> tag used together:
The information displayed ruby element consists of one or more characters (requires an explanation / pronunciation) providing the information and a rt elements, also includes an optional rp elements are defined when the browser does not support the "ruby" element when.
<Rp> tag is the new HTML 5 tags.
Tip: Support for "ruby" element of the browser does not display "rp" element.
<rp> tag supports HTML in the global properties .
<rp> tag supports HTML in the event properties .