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M What kind of problems WAP has

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The functionality of page in WAP-devices (Wireless Access Protocol) with CSS has two alternative. The first is a browser, which has a proper CSS-implementation. The second alternative is, that the WAP server can understand CSS. The WAP server could read firsst this part of the page:

<LINK rel="stylesheet" media="handheld" href="handheld.css">
<LINK rel="stylesheet" media="print" href="print.css">
<LINK rel="stylesheet" media="screen" href="screen.css">

Those kinds of files include declarations, how pages should be handled in mobile phones, palm pilots and other small devices or on printing and computer screens. The WAP server could keep the file in its memory in order to printing it. The media="print" could control the printing process.

I have heard that the WAP-server take off big image. But the process is out of the control of the author. If the server could understand CSS, the author and the server could both control the layout of the page. Same pages could be made both to WAP-devices and computer screens so that the author could always know how they work in different devices.

The identification of media type is the base of the whole system. Because CSS2 pays regard to WAP-devices, it could be extremely desirable that devices and WAP-servers could exploit CSS2-technology.

Media types

The media type handheld is problematic, becuse the ability to handle graphics is very limited in mobile phone (look at table from the page a table[Pw] from the page and a short explanation after it).

The media type tty can't be used, because it is text-only. Shoud there be a special media type mobile_phones? Then the type handheld concerns only palm pilot and other small handheld computers.

Link images

A link systems, which base on images are problematic. Pictures should not be primary linking elements. Pictures should be pictures and links should be text links! Especially problematic are so-called imagemaps. Imagemap-systems could be used with following way or they could be replaced with a CSS-based system:

In that way it is in fact easier to create much more flexible linking system as by using image maps. Indeed links are always rectangular. Users of old browsers might not see all image at all. It is not possible to define alternative background by using HTML 3.2 level background attributes for all elements. This is not however a basic level problem, because most browsers support CSS.

If same pages are used in handheld devices and large computer screens, in my mind imagemap systems should not be used at all. Instead of them I recommend to use alternative solutions. Image links should have alternative text links. They could be hided in the version (media="screen"), which is intended for ordinary computers. Browsers, which don't understand CSS view them. That's why also alternative text links should look out relative nice.

Scripts

For many people the most inconvenient feature might be, that most of scripts are harmful. The optimal situation is, that they are not used at all. They can't be used in mobile phones. Scripts can be used so, that they could have different versions to different devices. I have however made a proposal[Pw] to implement the media rule also into scripts.

Many scripts are useful but some of them are totally unnecessary. It is easy to give up from scripts, which exchange images. I had once in navigation frames about 150 links. They used following kind of CSS:

:link {...}
:visited {...}
.some_class a:hover {...}
.some_class a:active {...}
.some_class a:focus {...}
.some_class a:hover img {...}
.some_class a:active img {...}
.some_class a:focus img {...}

..., .some_border a:hover, ... {display:block;margin-right:1px;text-decoration: none}

If I had replaced navigation elements related images using four script event related image, I would need 600 images. It is common habit to use only two events (OnMouseOver / onMouseOut). Then the minimum quantity of images is about 300. The maximum replacing quantity was about 750 images (five different event handlers). These images might have taken about one megabyte (1 MB) hard disk space. CSS needed only few kilobytes (Kb). Compared to the large quantity of images almost nothing.

And If I would like to make exchanges. I write some minor exchange to the CSS-code. It is extremely easy to exchange the appearance on unlimited quantity of links in a minute. To make 300-750 images could take a lof of time. "Into the bargain" the advance is, that CSS doesn't cause any harm into the accessibility in small devices.

CSS save enormous quantity of graphic work! It is possible to create cheap pages both to computers and handheld devices. The graphic artists could create few backgrounds to links and elements, which works as parent elements of links. They could also create background to the whole page and make some basic images. There could be however much less work as in HTML 3.2 page designing.

This needs however exchanges in attitudes. People, who would use old browsers could suffer in the appearance of pages. But all could win in the speed. All could have less images and less an-reliable working scripts. If the appearance is not satisfactory, it is always possible to get free a new better working browser from the Internet.

The replacing CSS2-system works today only in MS IE and Mozilla Gecko browsers. In Opera browsers, which are older than Opera 7.0 Beta 2, background images don't work with dynamic pseudo-classes.

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CSS-guide has been last edited 07.08.2004