CodeHelp - glossary G

Added to HTML code by some WYSIWYG design tools to allow them to work out how many authors are willing to advertise their product free of charge. The value is not used by search engines and can be safely removed from any and all files in which it is found.
Top

The get method can be used from forms but forms should normally use the post method (W3C convention). Providing that the CGI script supports GET, you can use the method to activate the script with predefined data from an ordinary <a link: <a href = "myscript.pl?key=value&key2=value2" >LINK_TEXT</a> Note the lack of spaces between the script name (which could end in .cgi on some servers) and the GET data. Data needs to be passed as a key and a value - matching the key names used within the script.
Top

One of only a few universally recognized graphics formats for use on the web. Use .png files for all small images, any graphic using less than 256 colours or if you want to avoid patent issues with the GIF format. Photo quality images are best prepared as a second format, jpeg. Gif/png files are particularly useful for reducing the file size of images with areas of flat colour and are truly platform independent, so you can rely on the image looking the same to all visitors. (Note that dithering by the browser can still affect gif files viewed on low colour depth monitors and can be particularly noticeable with gif files that contain areas of small text.) Use gif files for logos, cartoon illustrations, icons and any image requiring transparency or which needs to be animated, either internally by the browser or as part of a Java applet. To make the most of the advantages offered within the gif format, keep your images small by cropping blank space from around the image. Scale down the image in your editing software instead of using width and height attributes in the HTML with values which are smaller than the real size. Use solid colours instead of gradients whenever possible and when changing an image from a higher colour depth to 256 colours for a gif file, beware of the editing software 'dithering' the image which will leave you with a grainy image and a larger file size than necessary.
Top

Key points with graphics

• Always use alternate text in the <img> tag. Remember to keep the alternate text brief yet descriptive.
• Use gif and jpeg files to their best advantage. If you use another format (e.g. Flash Shockwave) provide a link to a web site where users can download a plug-in or viewer. Some users may not able to view Flash at all - consider whether your content can also be made available using pages that don't depend on Flash.
• Never use a larger file than needed. Do all the hard work of reducing the file size and cropping the image in your editing software before uploading to the net. If visitors are kept waiting for your graphics they are likely to go elsewhere.
• Design your gif files to use the web palette to avoid dithering, especially with images that contain areas of text.
• Adapt existing files to use the nearest web palette colour in areas of flat colour.
• Reduce the colour depth of all your images until you achieve a balance between image quality and file size.
• Use the height and width attributes of the <img> tag. Once the file size and image size are optimized, specify the height and width to allow the browser to lay out the page before the file has finished downloading. Avoid using the attributes to increase or decrease the image size. This avoids the ugly sight of the browser having to redraw the page every time an image is ready to display. It also allows the visitor to read the alt text if images are not supported.

For detailed information on design of web graphics, see Web Design in a Nutshell by Niederst.
Top

Assign the same properties to a group of elements:
h1, h2, h3 {color:green;text-align:right;}
All h1, h2 and h3 headers in a document using this ruleset will be in green and aligned with the right margin. Other characteristics of the elements are not affected, in this case the changes in font size between the header elements will not be affected by this rule.
See also:

• # - the ID selector
• . - the class selector

Top