I tried the <input type="number" /> but on Opera that outputs a strange input box coupled with an "up and down" handler. What I expected was a regular text field that once you focus on it prompts the number keyboard instead of the alphabets. Is that even possible?
p.s. I'm not trying to validate. It would be a nice user experience, that's all.
type="number" is HTML5 and many phones do not support HTML5.
For call link you can use type="tel" or
<A href="wtai://wp/mc;600112233">Special A</A>.
You should look at CSS WAP extensions (page 56) too.
EDIT 10/2015:
Most if not ALL smart phones support HTML5 and CSS3, so type="number" is the best way.