APPENDIX: Brief introduction to HTML / Web pages

HTML is a simple language you can use to write web pages. Web pages have the potential to be very powerful for organizing information by using nested links to go into various levels of detail without losing track of the larger overall picture.

There are lots of HTML commands and capabilities, but basic usage is really simple! An HTML file is a simple text file that is interpreted by a web browser to show information.

In the Astronomy Department, if you use an address: http://astronomy.nmsu.edu/name, it will look for files in the directory /home/httpd/html/name. If the web address is a directory name, then the browser will look for a file called index.html in that directory and, if it exists, will display it; if it doesn't exist, it will display a directory listing of the file contents of that directory.

A HTML file contains the data (text, plots, etc) to be displayed, along with a set of HTML commands that controls to some extent how it will be displayed.

HTML files start with <HTML><BODY> and end with </BODY></HTML>; many HTML tags come in this same begin/end pairing where the end tag has a slash in it.

Inside the body, any text will just be displayed as a continous text stream in the browser, whether you put new lines, spaces, etc. in the HTML file. To control this more, you can use:

<br> forces a line break
<p> forces a paragraph break (like a line break but with some extra space)

Probably the most important HTML feature for organizing information is the feature that allows you to make hyperlinks to other HTML pages. This is accomplished using <a href=address> text </a> which will display the word text on the page, and it will be a link to the address specified by the href= parameter.

Other possibly useful features:

you can make lists using
- <UL> starts the list
- <LI> starts a new list element, with a bullet
- </UL> ends the list
- (<UL> </UL> make bulletized lists, <OL> </OL> makes ordered/numbered lists )
you can make tables using
- <TABLE> starts the table (use <TABLE BORDER=2> to show lines in table)
- <TR> starts a new row
- <TD> starts a new column in the current row
- </TABLE> ends the table
you can include images using
- <IMG src=filename> will display the image given by filename (assuming it's a format that the browser understands, usually GIF or JPG)
- This will display the image in its native size, you can control the size using <IMG src=filename WIDTH=x> where x can be a number of points, or often more useful, can be specified as a percentage of the page width, e.g. <IMG src=filename WIDTH=25%> will display an image that takes up 1/4th the width of the browser window.

There's of course LOTS more (fonts, colors, backgrounds, frames, etc etc) but you can go a long way with the basics.