Science and Computers -- PHY307/607

Simple HTML Reference

Web pages are constructed using the HyperText Markup Language HTML. This is a formatting language that describes how the various elements of a Web page should be rendered by the browser program. That is, it indicates the relative positions of various items of text and graphics - it does not specify details such as font, fontsize and color - such decisions are left to the browser. The idea is that this scheme allows the pages to be truly platform independent - a user's browser program substituting the most suitable fonts and colors available. It also renders it simple and easy to learn.

Formatting actions are determined by the use of tags. These can be of two types: empty tags and container tags. Examples of the former include the paragraph tag <P>, the horizontal rule tag <HR> and the line break tag <BR>. These are one-time instructions that the browser will obey.

Graphics may inlined using the image tag <IMG>. For example the file me.gif can be inlined to the page with the tags

Container tags specify formatting or construction for a range of selected text and graphics. They come in two types - beginning and ending. For example, the tag <H1> delineates the beginning of a heading and </H1> the end.

One special type of container tag is the anchor <A> tag - this is used to create a hyperlink - a highlighted piece of text or graphics which when clicked causes the browser to download the new Web page pointed to by the link. An example of such an embedded link might be

Container tags can be nested - they may also contain empty tags. The following are commonly used container tags

<H1>--<H5>.: Different sizes of heading font - from largest to smallest.
<UL>: Creates an unordered list with list items specified by the <LI> tag.
<OL>: Ordered list.
<DL>: Glossary list - elements are specified with the <DT> tag followed by inset descriptions marked with the <DD> tag.
<TITLE>: The title tag.
<BODY>: The tag surrounding the body of the Web page.
<HEAD>: A tag enclosing the TITLE and other preface tags.
<APPLET>: This tag allows one to embed a piece of Java code directly into the Web page.

A basic document template is given below. Note that these html instructions would be placed in a file called, for example, myfile.html.

<HTML>
<HEAD>
<TITLE> Some title or Other </TITLE>
</HEAD>
<BODY>
This is where your HTML goes
</BODY>
</HTML>

There are many more tags (particularly in the new HTML 3.0 specification) allowing for forms and tables, clickable image maps, customised bullets and a whole host of other features to be constructed. Documentation on these can be obtained from the Web. A good source of links for HTML info can be found here.

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This page maintained by Simon Catterall, last updated 21 August, 1997.