This is a little background information on HTML and URLs. For more information type mosaic http://fire.clarkson.edu/doc/html/htut.html ============================================================= HTML HTML documents consists of headers, paragraphs, lists, tables and figures. A simple example of an HTML document is: ------------------------------------------------------------- HTML Document Title

First level heading

Second level heading

Text lines that exceed the window width are automatically wrapped around by the viewer. Note italicized can be embedded within parts of a line of text if you wish.

This angle-bracket-p represents a new paragraph. Note that unlike title and header tags the matching end tag is not needed.

------------------------------------------------------------- This would look like (as best can be illustrated in this email at least) as follows where my comments are enclosed below in parentheses(): ------------------------------------------------------------- HTML Document Title (appears on separate line in Mosaic viewer) First level heading (24 point bold) (blank line inserted above) Second level heading (18 point bold) (blank line inserted above) Text lines that exceed the window width are automatically wrapped around by the viewer. Note italicized can be embedded within (begin italicized section) parts of a line of text (end italicized section) if you wish. (blank line inserted above) This angle-bracket-p represents a new paragraph. Note that unlike title and header tags the matching end tag is not needed. ------------------------------------------------------------- The document text includes tags which are labels giving formatting instructions to a viewer. Tags are represented as enclosed in . Many tags have matching end tags but not all as in the case for

. When a matching end tag is needed it is preceded by the "/" character as in the case for headers where

.....

. Tag and attribute names are not case sensitive. Unrecognized tags are ignored. There are tags for paragraphing, lists, headers, lists, tables, images, and figures. Tags may also be accompanied by attributes, e.g. in some tags the name destinations for hypertext links may be used. General HTML Structural tags ... encloses the entire html file ... encloses the document title ... encloses the header information such as title ... encloses the body of the document That is, an html document could have the format ... .... Headers ... encloses a header, where i=1,...,6 (levels of headers) Paragraphing tags note: Blank lines, tabs, newlines, and extra spaces are ignored in an HTML.

start new paragraph
carriage return

draw a long horizontal line 
 ....
text is written verbatim Lists note: Nesting is allowed with lists.
    numbered lists
  1. ... ...
  2. ...
definition lists
...
... text after
is all indented from text following
...
... ...
...
...
Font tags ... boldface ... italics ... fixed-width font ... underline Escapes (a space must come after each escape sequence) < for < > for > & for & " for " Unlike the fine control provided (e.g.) by LaTeX, HTML does not provide fine precise layout instructions; hence the viewer must make many decisions about exact layout and presentation. Different viewers will often render documents slightly differently because of the HTML imprecision. Sometime this is annoying when trying to specify exact font names and point size, the margins, tab settings and how much white space to leave before and after things. Subscripts and superscripts are not currently part of HTML but may be in the near future. ------------------------------------------------------------- URL URL stands for uniform resource locator. URL is a pointer to a file. There are many variations and subtleties about its format and interpretation. Of particular important and interest is that it can point to a file on a remote machine that has a world-wide-web node. One needs only to specify an access protocol, a machine name, and a relative file pathname. For example, http://www.eit.com/xyz/abc would mean: an access protocol http (hypertext transfer protocol), site name www.eit.com, and xyz/abc as the relative path to the file abc. For example, the URL to an anonymous ftp site, ftp.cs.brown.edu, and the file README would be: ftp://ftp.cs.brown.edu/README Interestingly Mosaic/WWW can transparently handle many different protocols including: ftp, gopher, and http. Links to Other Documents ... fname will be displayed, when text inbetween bracketted tags (which appears underlined) on the screen is clicked with mouse where the file extension on fname could be one of the following .txt plain text .html html markup text .gif image text .ps postscript Also, fname is one of two forms, 1. relative ex. When viewing the CS department home page //cs.nyu.edu/, the current directory is /usr/httpd/htdocs Within this home page, a link to Bob Paige's home page, which is stored in file /usr/httpd/htdocs/cs/faculty/paige/index.html, could be stored as a relative link in which "fname" would be cs/faculty/paige/index.html Within Bob Paige's home page directory, a relative link to ps file atlantique.ps, which is stored in that directory would just be atlantique.ps 2. absolute Here, fname has the form scheme: //host.domain/path/filename where scheme is, file file is on an anoymous ftp server http file is on a web server gopher file is on a gopher server -------------------------------------------------------------