HTML5 forms - HTML5 and CSS3 - page 58

The HTML5 spec therefore doesn't specify a format; the tel type is
basically the same as a text input other than in its semantic content. If
you want to enforce a particular format on the tel field, you'll have to
use the pattern attribute discussed in the section “The min, max, and
pattern attributes.”
Color pickers
Color isn't widespread in today's web forms. But because one of the
key focuses of HTML5 is to enable HTML applications, color pickers
are likely to be a more common requirement in the future. The first
implementation of the color input type is in Opera 11.
The HTML5 markup for a color picker is
<input type="color">
The default value is #000000 . Selected
values are always in #rrggbb hexadecimal
shorthand.
When the user expands the control, a
selection of common colors is presented.
Currently there's no way to configure this
set of colors, but clicking the Other button
brings up the full color picker.