elements <h1>, <h2>, <h3>, <h4>, <h5>,
and <h6> are used to specify headings (level 1 to level 6) in
an XHTML MP page. WAP browsers will try to display headings of
different levels with different font sizes and styles. However, some
WAP devices do not have so many sizes and styles of fonts and so
headings of different levels may look the same on the screen.