Availability and Efficiency
Making web sites available to as many people is possible is an important goal for any designer, as is making files that download quickly. To do both, be sparing with the size of the files and careful with their structure.
Text is the best way to do it and is also the easiest medium for creating web sites, as well as simplest and quickest to edit, proof, correct and to locate information in.
Photographs, other media than text
For comparison with files in other formats, the size of the file of a text document in html is about 2KB for contents of an average page in a book, or 200KB for 100 pages.
Here are four examples of the same photograph saved a 24 bit and an 8 bit png file and as a maximum quality and a low quality jpg files.
If you are placing photographic images in your sites, it is important to consider the size of the files and whether the lower resolution causes a loss of the meaning and feelings you want to get across.
And when you put something other than text in html up on a web site – pdfs, videos, audio files, animations, photographs, graphics – make sure:
- They add something text can not, otherwise it is a waste of peoplesʼ time and bandwidth.
- That content in them is accessible to those who can’t see or hear it and that it will work on different devices.
- That you are willing to have your site available only to those with a broadband connection, especially if what you have added is a video. (In 2013, less than 15% of the world's population has broadband (4 MB downstream), as compared with about one-half who have an internet connection.)
Video and media other than text.
- Some other things to be sure to consider when using videos, animations or information graphics based on images for teaching in place of text, with or without illustrations, are:
- How much more time does it take to watch and hear the information in a video or animation than to read it?
- Is the information graphic easy to follow and is it accessible?
- How easy is it to go back and review the material presented?
- How easy is it to search for a word, a sentence, a name, a chart or a diagram that was shown?
- How difficult is it to edit, update or correct other media compared to a text document?
- How many specialized skills do the different media require to produce and edit them? Are they available? How much will they add to the cost?
Using the application cache so that the files will be available to the user when they are offline is especially important as more and more people are using phones to access information on the internet and they are frequently without a connection or it is too expensive to use for long periods of time that reading a long text requires.
It involves including markup similar to this in the head of your page:
and making a cache manifest file and saving it to site directory – for example:
Although most browsers do cache files, using a cache manifest means there is enough space – 4M – given to it to store 4 or 5 book length html files.