Netscape Extensions

Netscape Extensions

Netscape extensions are unauthorized additions to the HTML 2.0 standard. Originally the Netscape extensions only worked with the Netscape Navigator browser. However, Mosaic 3.0+ browsers will support many of the Netscape extensions. If you use Netscape extensions in your document you should indicate this at the top of your document (see this tutorial's home page). Even though unauthorized, the Netscape extensions have become commonly excepted tags and are used in many Web documents. <CENTER>...</CENTER> The Center tags is one of the most popular Netscape extensions (see the HTML Center Tag below). The <CENTER> tag allows you to center text and graphics on a page. The banner image and divider bars on this page are all centered using the <CENTER> tag. <HR> Tag Attributes Netscape allows you to manipulate the size and width of the Line Rule tag.

The SIZE attribute indicates the thickness of the rule line (the default is 2).
- <HR SIZE="15">

The SIZE Attribute with NOSHADE
- <HR SIZE="15" NOSHADE>

The WIDTH Attribute with ALIGN: allows you to indicate the horizontal width of the rule line, either in pixels or as a percent of the page. The display resolution of the screen will effect the display.
- <HR ALIGN=CENTER WIDTH=80%
- <HR ALIGN=CENTER WIDTH=40%
- <HR ALIGN=CENTER WIDTH=20%
- <HR ALIGN=CENTER WIDTH=10%

Unordered List Tag Extensions

TYPE=DISC, for a solid bullet (the default)</LI>
TYPE=CIRCLE, for a hollow bullet
TYPE=SQUARE, for a square hollow bullet

Ordered List Tag Extensions

TYPE=1, the default, which labels the list item with numbers (1, 2, 3)
TYPE=A, orders list items with capital letters (A, B, C)
TYPE=a, orders list items with lowercase letters (a, b, c)
TYPE=I, orders the list items with capital roman numerals (I, II, III)
TYPE=i, orders the list items with lowercase roman numerals (i, ii, iii)
1. Introduction to HTML 2.0
  1. The World Wide Web
  2. Design Considerations
  3. HTML Structure
  4. HTML Tags
    1. Structure Tags
    2. Title & Heading Tags
2. Netscape Extensions
3. HTML 3.0

<OL TYPE=I>
      <LI>Introduction to HTML 2.0
        <OL TYPE=A>
         <LI>The World Wide Web</LI>
         <LI>Design Consideration</LI>
         <LI>HTML Structure</LI>
         <LI>HTML Tags
           <OL TYPE=1>
            <LI>Structure Tags</LI>
            <LI>Title & Heading Tags</LI></OL></LI></OL></LI>
      <LI>Netscape</LI>
      <LI>HTML 3.0</LI></OL>

... The font tag encloses text and prescribes the font size. This tag is controversial. By assigning font size, the this Netscape extension begins to control the format of a document and may undermine the flexibility and portability of HTML.

The values of font size are 1-7:

Font 1 Font 1</FONT.

Font 2 Font 2

Font 3 Font 3

Font 4 Font 4

Font 5 Font 5

Font 6 Font 6

Font 7 Font 7

You can also specify font size in relative terms by using the "+" or "-" characters. The font will change relative to the default font size of your browser. Use this extension with caution, it may cause problems for your users. For example, if a user has set their browser for 16 pitch Time Roman because they need larger print, setting your font with a minus value might cause them difficulty in reading the text. Your positive values may cause the text to be too large on their screen.

Relative font size:

Font +3 Font +3

Font -3 Font -3

Backgrounds The background attributes allow you to add images as backdrops to your document, as well as manipulate the background color, text, and link colors of a document. The most important thing to consider when using these tags is the readability of your documents. There are many examples of the improper use of these tags on the Web. I have come across backgrounds that make it almost impossible for the user to read the text. Make sure you test your backgrounds thoroughly before you mount them. Use an image editor like Paint Shop Pro to fade your backgrounds until the text of your document is readable. It is important to remember that background images add to the size of your document and will take more time to load. If most of your users access your pages using 14.4 modems you may not want to use the background color attribute.

Background attributes are inserted into the <BODY> tag.

<BODY BACKGROUND="../image/purple.gif>
- This element tells the browser to find the file "purple.gif" in the image directory, and display it as a background. This particular background is used on the home page of this tutorial. Display the source code of the home page to see the element. Here are some other examples:
<BODY BGCOLOR="#E5E2FF">
- This element tells the browser to display the background color as something other than the default background (grey). In this example the color is #FFFFCC which is the background of this page. To manipulate background colors easily you should get a color editor such as the Web Color Editor 1.0 by Aleksei Taranov. The BGCOLOR attribute can be used as an alternative to the BACKGROUND attribute if your users are running 14.4 modems. Other attributes that can be added are:
 - TEXT, which controls the color of all the regular text in the document
 - LINK, which controls the color of the normal unvisited links
 - VLINK, which controls the color of the visited links
 - ALINK, which controls the color of the link as you press your mouse button on the link
- The background attributes for this page are as follows:
 <BODY BGCOLOR="E5E2FF" TEXT="000000" LINK="0000FF" VLINK="FF0000" ALINK="EE009B">

<BLINK>...</BLINK> The blink tag causes your text to blink on and off. Depending on the version of Netscape your users are using, either the text itself will blink, or a white block will blink on and off behind your text. This tag is used to call attention to a specific item. Use this tag with caution, it has a tendency to annoy many users.

Go To FRAMES

These pages were produced by Thomas Eland using the following software: HoTMetaL PRO 2.0; HotDog 1.3.1; Paint Shop PRO; Color Manipulation Device; and Aldus Presentation software. The pages were produced on a Packard Bell Force 949CDT 120 MHz with 24 MB RAM using Windows 3.11 for Workgroups. The pages were tested using Netscape 2.0 and Spry Mosaic 2.0a. Questions and responses are welcome, and can be sent to me at: tweland@mm.com