The bulk of a web page consists of paragraphs, structured with the use of headings. The two kinds of elements are described in the following.
p element is used to split text into paragraphs.
<p>An introductory paragraph.</p> <p>Another introductory paragraph.</p>
There are six levels of headings. The most important heading(s) in a document should be level one. Sub-headings should be level two. Sub-sub-headings should be level three, etc. Do not skip levels. If the default sizes do not suit your document, use CSS to change them. Headings should be used to effectively outline your content. By doing so, users can find information more quickly (i.e. wikipedia), and some search engines use headings to help rank page content.
<h1>This is Level 1</h1>
<h3>This is Level 3</h3>
<h5>This is Level 5</h5>
This example will be used in the next section where we see how to change the appearance of a document.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html lang="en"> <head> <title>Sundial</title> </head> <body> <h1>Sundial</h1> <p>From Wikipedia, the free encyclopedia.</p> <p>A sundial measures time by the position of the sun. The most commonly seen designs, such as the 'ordinary' or standard garden sundial, cast a shadow on a flat surface marked with the hours of the day. As the position of the sun changes, the time indicated by the shadow changes. However, sundials can be designed for any surface where a fixed object casts a predictable shadow. </p> <p>Most sundial designs indicate apparent solar time. Minor design variations can measure standard and daylight saving time, as well. </p> <h2>History</h2> <p>Sundials in the form of obelisks (3500 BC) and shadow clocks (1500 BC) are known from ancient Egypt, and were developed further by other cultures, including the Chinese, Greek, and Roman cultures. A type of sundial without gnomon is described in the old Old Testament (Isaiah 38:2). </p> <p>The mathematician and astronomer Theodosius of Bithynia (ca. 160 BC-ca. 100 BC) is said to have invented a universal sundial that could be used anywhere on Earth. The French astronomer Oronce Finé constructed a sundial of ivory in 1524. The Italian astronomer Giovanni Padovani published a treatise on the sundial in 1570, in which he included instructions for the manufacture and laying out of mural (vertical) and horizontal sundials. Giuseppe Biancani's Constructio instrumenti ad horologia solaria discusses how to make a perfect sundial, with accompanying illustrations. </p> <h3>Installation of standard sundials</h3> <p>Many ornamental sundials are designed to be used at 45 degrees north. By tilting such a sundial, it may be installed so that it will keep time. However, some mass-produced garden sundials are inaccurate because of poor design and cannot be corrected. A sundial designed for one latitude can be adjusted for use at another latitude by tilting its base so that its style or gnomon is parallel to the Earth's axis of rotation, so that it points at the north celestial pole in the northern hemisphere, or the south celestial pole in the southern hemisphere. </p> <p>A local standard time zone is nominally 15 degrees wide, but may be modified to follow geographic and political boundaries. A sundial can be rotated around its style or gnomon (which must remain pointed at the celestial pole) to adjust to the local time zone. In most cases, a rotation in the range of 7.5 degrees east to 23 degrees west suffices. </p> <p>To correct for daylight saving time, a face needs two sets of numerals or a correction table. An informal standard is to have numerals in hot colors for summer, and in cool colors for winter. Rotating the sundial will not work well because most sundials do not have equal hour angles. </p> <p>Ordinary sundials do not correct apparent solar time to clock time. There is a 15 minute variation through the year, known as the equation of time, because the Earth's orbit is slightly elliptical and its axis is tilted relative to the plane of its orbit. A quality sundial will include a permanently-mounted table or graph giving this correction for at least each month of the year. Some more-complex sundials have curved hour-lines, curved gnomons or other arrangements to directly display the clock time. </p> </body> </html>