kana=""

a 要素 kana 属性、 telbook 属性 (HTML)

[1] <http://www.nttdocomo.co.jp/service/imode/make/content/browser/html/tag/tel.html>

[2] <http://www.nttdocomo.co.jp/service/imode/make/content/browser/html/tag/tel-av.html>

[3] telbook cannot contain emoji symbols; kana can only contain halfwidth katakana characters; they have length constraint