Question

I don’t quite understand the SWFObject examples downloaded http://download.macromedia.com/pub/developer/alternative_content_examples.zip’>here.

Why the availability of the flash plugin is checked only by
<|–[if !IE]> –> instructions.
Does it mean that just IE can be without preintalled flash player? Of course no. Then why
just IE is checked?

Answer 1

No! The code doesn’t mean it only check IE.

There are two example in the zip, first one is

<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="728" height="90" id="myFlashContent">
    <param name="movie" value="banner.swf" />
    <!--[if !IE]>-->
    <object type="application/x-shockwave-flash" data="banner.swf" width="728" height="90">
    <!--<![endif]-->
        <img src="banner.jpg" alt="Alternative content rules!" />
    <!--[if !IE]>-->
    </object>
    <!--<![endif]-->
</object>

second one is:

<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="480" height="270" id="myFlashContent">
    <param name="movie" value="movie.swf" />
    <!--[if !IE]>-->
    <object type="application/x-shockwave-flash" data="movie.swf" width="480" height="270">
    <!--<![endif]-->
        <ol>
            <li><img src="frame1.jpg" alt="" />It's night-time, a UFO flies over the pasture, cows grazing</li>
            <li><img src="frame2.jpg" alt="" />The UFO tries to abduct two cows using a tractorbeam, however the cows appear to be too heavy to be lifted off the ground</li>
            <li><img src="frame3.jpg" alt="" />It's daytime again, cows are still grazing, one cow looks very relieved</li>
        </ol>
    <!--[if !IE]>-->
    </object>
    <!--<![endif]-->
</object>

<!--[if !IE]>--> and <!--<![endif]--> works as a pair. They are just like if (!isIE){ //... }. And what it means is IE will ignore the code inside the pair (pay attention to the ! which means “not”). They are actually not related to Flash detection.

Flash detection(in fact it’s graceful degradation) is done by using the characteristic that when the plug-in is not present, its object/embed tag will be ignored and the HTML inside those tags will be displayed.

If Flash is not present, for the first one, <img src="banner.jpg" alt="Alternative content rules!" /> will be displayed. For the second, it’s

<ol>
    <li><img src="frame1.jpg" alt="" />It's night-time, a UFO flies over the pasture, cows grazing</li>
    <li><img src="frame2.jpg" alt="" />The UFO tries to abduct two cows using a tractorbeam, however the cows appear to be too heavy to be lifted off the ground</li>
    <li><img src="frame3.jpg" alt="" />It's daytime again, cows are still grazing, one cow looks very relieved</li>
</ol>