Re: help with arrays
- From: "Trevor L." <Trevor_L.@Canberra>
- Date: Sat, 8 Jul 2006 10:32:41 +1000
Kevin Spencer wrote:
You're too kind, Trevor. In fact, I agree with you that "it's horribly
complex." There are no external JavaScripts in the page, only 2 script
blocks.
The tags you found so confusing are in fact, simply non-existant HTML
tags. I can't remember seeing them used this way before, but browsers
will ignore tags they don't recognize, so they were probably used in
the same way as comments (not at all standards-compliant, but works).
The most complex aspect of the code is the use of objects. JavaScript
is "pseudo-object-oriented" in that you can define objects in
JavaScript, but they are variant objects, and do not support
encapsulation, inheritance, and polymorphism in the way that true OOP
does. A JavaScript object is basically an aggregate of process and
data that can be changed in structure at any time. Because such
objects are variant in nature, it's pretty hard to follow the code in
such a script. It can be done, but it's a rather painstaking process.
The script also uses browser-detection, which is fairly
straightforward, and cryptic naming, which is not. On first blush, it
looks like what it's doing is using an array of images, combined with
an array of URLs, to build dynamically a changing image that, when
clicked, opens a new window with the URL of the current image loaded
in it.
Unfortunately, I just don't have the hour or so to take it apart.
Well, thanks for that info. - great stuff as always, which I need to digest.
I am glad that I wasn't alone in thinking this would be difficult to decipher
I wonder whether the OP would not be better off rewriting the whole thing using "plain" J(ava)Script, i.e., just set up an array of
images, and a button which invokes a JS function which simply uses setInterval to cycle through the images. The same button could
also be used to stop the cycling.
Here is a function which does a similar task
<script type = "text/javascript">
var ss_run, ss_lock = false
function auto()
{
if (!ss_lock)
ss_run = setInterval("chgImg(1)", 5000)
else
window.clearInterval(ss_run)
ss_lock = !ss_lock
}
</script>
It is invoked by
<input type="button" size="10" value="Start/Stop Slideshow" onclick="auto()" />
chgImg is simply a function which increments a global counter and retrieves the next image from the array into id = "slide"
<img id="slide" src="" alt="" />
The basics of it are (array example from my site):
var ss_ImgNum = 0
var Pictures = new Array(
"0000-90-nessie" ,
"01-03-16-michelles-birth-16th-march-2001" ,
"02-01-27-michelle-10mths" ,
"02-06-06-phil-and-michelle" ,
"02-11-03-melissa" ,
"04-11-22-kate-and-julie" ,
"04-01-21-6-adam-on-sprinkler" ,
"04-01-21-bryan-on-sprinkler")
function chgImg(){
document.getElementById('slide').src = "images/" + Pictures[ss_ImgNum] + ".jpg"
ss_ImgNum ++
if (ss_ImgNum >= Pictures.length)
ss_imgNum = 0
}
My function has more than this in it; I have just extracted what I think is important and made a few (untested) changes
--
Cheers,
Trevor L.
Website: http://tandcl.homemail.com.au
.
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- Re: help with arrays
- From: Kevin Spencer
- Re: help with arrays
- From: Trevor L.
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